Searching for Hidden Costs:
A Technology-Based Approach to the
Energy Efficiency Gap in Light-Duty
Vehicles
Draft
&EPA
United States
Environmental Protection
Agency
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Searching for Hidden Costs:
A Technology-Based Approach to the
Energy Efficiency Gap in Light-Duty
Vehicles
Draft
Assessment and Standards Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
NOTICE
This technical report does not necessarily represent final EPA decisions or
positions. It is intended to present technical analysis of issues using data
that are currently available. The purpose in the release of such reports is to
facilitate the exchange of technical information and to inform the public of
technical developments.
&EPA
United States
Environmental Protection
Agency
EPA-420-D-15-010
November 2015
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Searching for Hidden Costs: A Technology-Based Approach to the Energy Efficiency Gap in
Light-Duty Vehicles
Gloria Helfand,* Jean-Marie Revelt,* Lawrence Reichle,** Kevin Bolon,* Michael
McWilliams,** Mandy Sha,*** Amanda Smith,*** and Robert Beach***
October 26, 2015
Abstract
The benefit-cost analysis of standards to reduce vehicle greenhouse gas emissions and
improve fuel economy by the U.S. Environmental Protection Agency (EPA) and the Department
of Transportation (DOT) displayed large net benefits from fuel savings for new vehicle buyers.
This finding pointed to an energy efficiency gap: the amount of energy-saving technology
provided in private markets appeared not to include all the technologies that produce net private
benefits. The finding of a gap involves three pathways. First, the energy-saving technologies
must be effective in achieving fuel reductions. Second, the cost estimates for those technologies
must be lower than the present value of fuel reductions. Third, possible "hidden costs" -
undesirable aspects of the new technologies - must not exceed the net financial benefits. This
study examines the existence of hidden costs in energy-saving technologies through a content
analysis of auto reviews of model-year 2014 vehicles.
Content analysis involves systematic identification in texts or other media of key
concepts and coding of those concepts; qualitative assessments can be quantified for statistical
analysis. Auto reviewers, as professional evaluators, are likely to be sensitive to the existence of
positive and negative characteristics of vehicles. Although they may identify hidden costs that
some vehicle owners may not notice, it is relatively unlikely that they would miss important
problems.
Results suggest that it is possible to use fuel-saving technologies on vehicles without
imposing hidden costs. For each of the technologies examined, the number of reviews that
evaluated them positively exceeded the number that spoke negatively. There is scant evidence in
this analysis of a robust relationship between the technologies and vehicles' operational
characteristics, such as handling or acceleration. It seems possible to implement these
technologies without adverse effects on vehicle quality; hidden costs do not appear to explain the
efficiency gap for vehicle fuel-saving technologies.
*Office of Transportation and Air Quality, U.S. Environmental Protection Agency
**Oak Ridge Institute for Science and Education (ORISE) Research Participant
***RTI International
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Searching for Hidden Costs: A Technology-Based Approach to the Energy Efficiency Gap in
Light-Duty Vehicles
When the U.S. Environmental Protection Agency (EPA) and the Department of
Transportation (DOT) developed standards to reduce vehicle greenhouse gas emissions and
improve fuel economy, they estimated significant net benefits to the standards, with the largest
benefits coming from fuel savings to new vehicle buyers; indeed, the fuel savings greatly
exceeded the costs of technologies that would provide those savings (EPA and DOT 2010,
2012). This finding pointed to an energy efficiency gap, also known as the energy paradox: the
amount of energy-saving technology provided in private markets appears not to include all the
technologies that produce net private benefits. For instance, although six-speed automatic
transmissions have existed for a number of years, and appear to have a payback period of
approximately one year relative to four-speed transmissions (Helfand and Dorsey-Palmateer
2015), they were uncommon in new vehicles until very recently (Hula et al. 2014). Various
authors are skeptical of these estimated savings, on the basis that, if they provided the benefits
claimed, private markets should have led to their adoption (e.g., Allcott and Greenstone 2012).
On the other hand, if the gap exists, then it is possible for energy efficiency regulations not only
to address externalities, but to save consumers money (Fischer et al. 2007). The existence of the
gap, then, has significant implications for the net benefits associated with energy efficiency
requirements.
A number of studies explore consumer or producer behavior at the point of deciding
when to invest in energy-saving technologies (see, e.g., Helfand and Wolverton 2011; Allcott
and Greenstone 2012; Gillingham and Palmer 2014). This study focuses instead on post-
decision welfare - experienced utility, instead of decision utility (e.g., Kahneman and Sugden
2005) - to examine the existence of the efficiency gap. With the standards in place, the
existence of the gap is, in principle, an empirical matter.
The finding of a gap involves three pathways. First, the technologies to improve fuel
economy must be effective in achieving their fuel reductions. Second, the cost estimates for
those fuel-saving technologies must be lower than the present value of the fuel reductions. These
first two elements define the engineering analysis that is commonly the source of identified
efficiency gaps.
The third element of the gap is the possible existence of "hidden costs" of the
technologies: undesirable aspects of the new technologies. For instance, if six-speed automatic
transmissions were especially noisy, clunky, or otherwise worse to drive than four-speed
automatic transmissions, those quality impacts would reflect losses to consumer welfare that the
engineering analysis would not capture (Gillingham and Palmer 2014), and might potentially
close the gap. An evaluation of the new technologies should consider these costs.
This study examines the existence of hidden costs in fuel-saving technologies through a
content analysis of auto reviews of model-year 2014 vehicles. Content analysis is a method to
analyze text for patterns and meaning (Krippendorff 2013). It involves systematic identification
of key concepts and coding of those concepts; in other words, qualitative assessments can be
quantified for statistical analysis.
The study findings suggest that it is possible to use fuel-saving technologies on vehicles
without imposing hidden costs. For each of the technologies, the number of reviews that spoke
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positively about the technology exceeded the number that spoke negatively of them. We also
find few signs that any of the technologies contribute to negative ratings of vehicle operating
characteristics, such as handling or acceleration. That there is variation in success suggests that
there may be room for improvement: for example, some technologies may have been
implemented more effectively in some vehicles than in others. Nevertheless, this analysis does
not find evidence, beyond perhaps short-run implementation concerns, that hidden costs of these
fuel-saving technologies explain the existence of the energy efficiency gap in vehicles.
The next section of this paper provides the policy background for this work. Next, we
describe content analysis, the method used for this study, and the details of the data collection.
The results and conclusions follow.
In 2010 and 2012, EPA and DOT issued joint standards to reduce the greenhouse gas
(GHG) emissions and increase the fuel economy (FE) from new vehicles for model-years (MY)
2012 through 2025 (EPA and DOT 2010, 2012). By 2025, the standards are projected to achieve
a fleetwide average emissions level of 163 grams/mile of carbon dioxide, approximately half the
emissions of an average MY 2010 vehicle. If all the improvements in GHG emissions come
from improvements in fuel economy, the standards are projected to lead to fleet average fuel
economy of 54.5 miles per gallon (mpg).
The standards themselves are not these values. Instead, each vehicle has a target value
for GHG and FE based on its footprint, the area between its wheels. Larger vehicles have less
stringent targets than smaller vehicles. Each automaker has its own individual fleetwide average
standard based on the sales-weighted footprints of the vehicles that it makes in a given model
year. If a manufacturer produces more small vehicles, for instance, it will have a more stringent
target than a manufacturer that produces more large vehicles. This approach is intended to
protect the range of vehicles available to the auto-buying public, to avoid the risk of unfairly
benefiting one manufacturer over another, to allow for flexibility in sales mix in the face of shifts
in market conditions, and to provide incentives to improve GHG emissions and FE across the
entire fleet.l Within an automaker's fleet, if some vehicles outperform their targets, they
generate credits that may be applied to vehicles that do not meet the targets in its own fleet,
banked for use in future years, retired, or sold to another automaker whose fleet does not achieve
its target.
EPA's and DOT's assessments of the standards found enormous net benefits, most of
which came from the projected fuel savings. For instance, in EPA and DOT (2010), EPA
projected that the average cost increase for a MY 2016 vehicle would be about $950, compared
to reduced fuel expenditures of about $4000 over the lifetime of that vehicle; the payback period
on the initial $950 was estimated at under 3 years. Because these net benefits to vehicle buyers
appear so substantial, the question arose why market forces did not bring them into place without
regulation. This phenomenon - the finding of cost-effective technologies to save energy that are
not in widespread use - has been observed in various settings, such as building insulation and
household appliances. Indeed, it is common enough to have a name - the energy paradox, or
1 A flat standard, which was in force for the first four decades of fuel economy requirements, may
encourage compliance by producing small but fuel-efficient vehicles that cross-subsidize large, inefficient vehicles.
The footprint-based standard reduces incentives for downsizing. Whether, as Whitefoot and Skerlos (2012) suggest,
it provides an incentive for increasing vehicle size depends on the slope of the footprint curve.
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energy efficiency gap (Helfand and Wolverton 2011; Allcott and Greenstone 2012; Gillingham
and Palmer 2014).
If the gap is real - that is, the present-value savings in energy costs outweigh all the costs
of the energy-saving technology - then private markets appear not to be behaving in standard
ways. A number of hypotheses have been raised to explain this behavior (Helfand and
Wolverton 2011; Allcott and Greenstone 2012; Gillingham and Palmer 2014), such as imperfect
information, excessive consumer discounting, or lack of salience of energy consumption as a
product characteristic. Behavioral economists have found evidence of behavioral anomalies in
market transactions (e.g., DellaVigna 2009). Specifically in the auto market, evidence is mixed:
Busse et al. (2013) and Sallee, West, and Fann (2015) found that vehicle buyers' revealed
willingness to pay for fuel economy approximately matches their future fuel expenditures, while
Allcott and Wozny (2014) estimated that vehicle buyers are willing to pay about 76 percent of
the value of future fuel savings, and Greene (2010) finds a wide variation in estimates of
consumer willingness to pay for fuel economy.
On the other hand, it is possible that the gap does not actually exist, despite the
engineering estimates. The engineering estimates may be wrong in three dimensions: they may
underestimate the monetary costs; they may overstate the monetary benefits; or they may ignore
"hidden costs," undesirable changes in other attributes of the product. Allcott and Greenstone
(2012) cite some examples of underestimated costs and overestimated benefits, as well as the
difficulties in doing good studies of these effects.
This study focuses on the question of the existence of the energy efficiency gap. In
particular, it examines the question of hidden costs as a potential explanation of the energy
efficiency gap in light-duty vehicles. If compliance with the standards adversely affect a
vehicle's power, handling, comfort, or other attributes, then potential vehicle buyers are likely to
be less interested in purchasing them, and fuel-saving technologies will face obstacles in
penetrating into the market. The existence and magnitude of hidden costs would, as noted, also
contribute to skepticism about the existence of the energy efficiency gap. On the other hand, if
fuel-saving technologies can be implemented without imposing hidden costs, then this
explanation of the efficiency gap is not supported.
Many vehicle attributes of great importance to vehicle buyers are qualitative. For
instance, while it is possible to measure the turning radius of a vehicle, how it feels while going
around a curve - the handling - is more difficult to quantify. Whether a fuel-saving technology
makes the vehicle uncomfortable to drive in some way may thus be an unquantifiable attribute.
For this reason, we looked to a method, content analysis, that can summarize a large quantity of
text and contexts into meaningful analysis units, to understand the effects of fuel-saving
technologies on vehicle quality.
Content analysis is a method to analyze text in a systematic way. It is widely used in the
humanities and social sciences to classify, measure, and evaluate themes and symbols in various
communications media (Krippendorff 2013). At the simplest level, content analysis can involve
counting mentions of words (as in word clouds), to highlight major topics or phrasings. In more
complex situations, content analysis can involve coding to identify subtle messages; for instance,
Ganahl et al. (2003) analyzed prime time television commercials in 1998 to examine the
prevalence of genders and ages, and found women (especially older women) underrepresented
relative to men.
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Most of the studies of content analyses involving automobiles focus on the issue of safety
in vehicle advertisements. Burns and Lynch (2003) found, in response to new safety
requirements in 1979, that vehicle advertisements increased their mentions of safety features, but
not safety itself. Ferguson et al. (2003) found that performance was the dominant advertising
theme in U.S. television commercials for cars and passenger vans; safety was mentioned
infrequently. Sheehan et al. (2006) examined television advertisements in Australia to examine
the effect of new requirements on auto advertising on the ads themselves; they found a reduction
in the occurrence of themes (Performance, Exciting/Fun to Drive) which could be considered to
promote unsafe driving, though safety themes were in a very small proportion of ads.
A few content analyses have considered the environmental effects of vehicles. Pollack
and Zint (2006) found that newspaper coverage of hybrid electric vehicles focused on the
vehicles' environmental attributes, rather than other attributes that consumers might consider
important when buying new vehicles. Wilson et al. (2008) analyze the content of New Zealand
vehicle advertisements for greenhouse gas (GHG) and air pollution-related information. In their
study, very few ads mentioned the vehicle's fuel efficiency or reduced emissions. Nygren et al.
consider the Finnish reform of the tax on purchase of new vehicles that increased the charge for
higher-GHG-emitting vehicles and reduced the charge for lower-emissions vehicles. They found
that newspaper coverage was generally positive and "treated [the reform] as an apolitical,
technocratic issue," though the authors express concern that the low level of coverage may have
led to an over-optimistic assessment of its impacts. These studies do not, however, look
specifically at the relationship between the environmental characteristics of vehicles and
consumer response to them, as this study does.
We chose content analysis as a tool to look for the adverse consequences of fuel-saving
technologies, because these adverse effects are likely to show up in qualitative descriptions. A
high-speed automatic transmission may shift roughly, for instance, or low rolling resistance tires
may not grip the road well. Professional auto reviews are expected to be a fairly sensitive and
relatively objective source of these qualitative descriptions. Auto reviewers are professional
evaluators, trained to identify positive and negative characteristics of vehicles. Although they
may identify hidden costs that some vehicle owners may not notice, it is relatively unlikely that
they would miss important problems.
The first part of the study involved selection of auto reviews to be analyzed. We followed
a conceptual hierarchy to choose relevant websites in multiple stages, consistent with the practice
of relevance sampling described in Krippendorff (2013). We sought websites on the first page of
search returns for keywords "new cars," "buying a new car" and "auto reviews," and excluded
websites that did not have national and professional auto reviews. We then used monthly unique
views from Quantcast.com and Compete.com to gauge Website popularity, excluded websites
that had less than one million unique views, and added a few websites that Compete.com
considered similar (to reduce any bias from using websites on the first page of search results).
Finally, we screened websites to ensure that reviews had an independent assessment of vehicle
quality (rather than a list of specification), and evidence of test driving of the reviewed vehicles.2
This process resulted in our using the six websites in Table 1. Though these reviews are not
2 Test driving was considered important so that reviewers would be able to evaluate operational
characteristics, such as performance, handling, and noise.
5
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necessarily representative of all auto reviews, they represent the reviews that vehicle buyers may
be most likely to see, and may therefore influence more buyers than other sites.
Table 1. Auto Reviews by Website*
Website
automobilemag.com
autotrader.com
caranddriver. com
consumerreports.org
edmunds.com
motortrend.com
Total
Initial Review
Counts
145
233
221
88
113
223
1,023
Final Review
Counts
144
225
218
88
112
221
1,008
Matched with
Tech Data**
98
163
153
39
109
157
719
* After the coding was completed, we identified 15 reviews of medium-duty
trucks that we considered out-of-sample.
** Vehicles with enough trim-specific information to link to a database that
identifies which technologies are on which vehicles
The study examined all reviews of new model-year 2014 vehicles available for sale in the
U.S. and subject to the light-duty GHG and FE standards that included evaluation after a test
drive. After dropping reviews that did not meet these criteria, and splitting reviews that included
discussion of more than one vehicle trim, the study coded 1,023 reviews. During the data
cleaning process, we identified 15 reviews of medium-duty vehicles that are not subject to the
light-duty GHG or FE standards; these were removed from the database. In addition, due to
notice of violations from EPA regarding certain Volkswagen and Audi diesel engines and their
emissions, we dropped 5 reviews of vehicles with those engines from our analysis (EPA 2015).
Analyzing the relationship between operational characteristics and efficiency
technologies might lead to biased results if reviewers do not discuss all the fuel-saving
technologies on the list when the vehicles have them. To address this concern, we linked the
vehicles in the content analysis with technology characteristics from publicly available EPA
data, which is used by EPA and the Department of Energy to generate the annual Fuel Economy
Guides. This information was supplemented with data from other publicly available sources,
such as Edmunds and Wards, for several technology characteristics that were not available in the
EPA data. These data are not available for all of the coded efficiency technologies in our review
database. In particular, excluded technologies are active air dam, active grille shutters, active ride
height, lighting-LED, mass reduction, and passive aerodynamics in addition to the general
categories: general engine, general transmission, and general powertrain. Linking the technology
data with the review data requires knowing the specific trim of each vehicle. In the review
database, we did not have detailed enough information on 289 vehicles (29%) to match them
with the technology database. After data cleaning, analyses involving the technology data (Tech
Data in the tables that follow) use 718 reviews.
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Reviews are themselves not conducted randomly or to reflect sales. For instance, as seen
in Table 2, the dataset contains more reviews of Mercedes (74) than Toyota (63) vehicles. The
review sites also sample differently: Consumer Reports reviewed 3 Mercedes (3.4 percent out of
88 reviews), while Car and Driver reviewed 26 Mercedes, 11.9 percent out of 218 reviews. It is
possible that auto reviewers focus on models with significant redesign; if so, the population of
reviews is likely to have a higher proportion of new technologies than the auto population as a
whole. The effect of this bias on the results of the analysis are unclear. To the extent that the
new technologies are actually new to the vehicle fleet, rather than new to a particular model, this
study may include more technologies where any kinks are not yet fully resolved, and thus may
overstate negative impacts experienced over time.
Table 2 also compares the total reviews to the number of distinct vehicles on the market
for each make using data available from fueleconomy.gov. That is, it compares the proportion of
models offered by each make to the proportion of reviews. The percentages differ by 1% or less
for most manufacturers, suggesting that sampling bias across makes is small relative to the fleet
of available vehicles. It is important to note that a particular make-model-trim combination may
be reviewed several times across websites and therefore counted more than once in the "Total
Reviews" column, while it will only be listed once in the fueleconomy.gov column; and some
make-model-trim combinations may not be represented in the reviews. Still, this suggests that
reviews may be roughly representative of vehicles offered, even if they are not representative of
vehicles sold.
Similar evidence is presented in Table 3, which lists counts by vehicle class and again
compares with the vehicle listing from fueleconomy.gov. The most reviewed class is midsize
cars with 23%, followed by compact cars (17%), and small SUVs (14%). Again, the majority of
classes are within 1% of the national fleet-wide percentages. The most notable exception is
midsize cars, which represents 17% of the fleet of available vehicles. There is no reason to
expect the distribution of reviews to exactly match the distribution of available cars, since
reviews will be determined by other factors, such as the redesign cycles of vehicles. However,
we are encouraged by the similarity in our sample as it suggests we have a reasonable view of
available vehicles and the corresponding technology.
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Table 2. Auto reviews by website and make; compared with fueleconomy.gov counts*
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Make •< g •< O Q U Cg H S H g H <£ U
Acura 445245 24 (2%) 22 (3%) 16 (1%)
Audi 3 11 9 176 37 (4%) 32 (4%) 48 (4%)
Bentley 2 5 4 11 (1%) 11 (2%) 7 (1%)
BMW 13 11 19 3 7 16 69 (7%) 51 (7%) 98 (8%)
Buick 73 6 128 27 (3%) 13 (2%) 16 (1%)
Cadillac 88 6 1 3 10 36 (4%) 17 (2%) 35 (3%)
Chevrolet 15 16 20 10 8 16 85 (8%) 62 (9%) 77 (6%)
Chrysler 12 1 4 (0.4%) 4 (1%) 14 (1%)
Dodge 273354 24 (2%) 16 (2%) 35 (3%)
Ferrari 31 37 (1%) 4 (1%) 13 (1%)
Fiat 1 32118 (1%) 4 (1%) 7 (1%)
Ford 5 14 7 5 5 11 47 (5%) 34 (5%) 88 (7%)
CMC 1741 4 17 (2%) 2 (0.3%) 36 (3%)
Honda 584548 34 (3%) 29 (4%) 30 (2%)
Hyundai 92 4 4 19 (2%) 16 (2%) 38 (3%)
Infiniti 394135 25 (2%) 22 (3%) 29 (2%)
Jaguar 468 2 8 28 (3%) 18 (3%) 20 (2%)
Jeep 6 8 10 10 4 4 42 (4%) 27 (4%) 35 (3%)
Kia 7 10 10 557 44 (4%) 38 (5%) 35 (3%)
Land Rover 333213 15 (1%) 9 (1%) 13 (1%)
Lexus 234356 23 (2%) 14 (2%) 25 (2%)
Lincoln 31 26 (1%) 6 (1%) 16 (1%)
Mazda 8 9 9 4 6 13 49 (5%) 33 (5%) 25 (2%)
Mercedes 6 14 26 3 6 19 74 (7%) 56 (8%) 85 (7%)
Mini Cooper 511 4 11 (1%) 9 (1%) 46 (4%)
Mitsubishi 342323 17 (2%) 12 (2%) 19 (2%)
Nissan 4 19 6 254 40 (4%) 38 (5%) 51 (4%)
Porsche 6 3 13 129 34 (3%) 25 (3%) 52 (4%)
Ram 211 12 7 (1%) 1 (0.1%) 13 (1%)
Rolls Royce 3 1 239 (1%) 9 (1%) 7 (1%)
Scion 11 11 4 (0.4%) 3 (0.4%) 9 (1%)
Smart 1 1 (0.1%) 1 (0.1%) 4 (0.3%)
Subaru 452338 25 (2%) 17 (2%) 23
Toyota 6 17 14 5 7 14 63 (6%) 40 (6%) 58
Volkswagen** 16 9 11 6 4 37 (4%) 21 (3%) 50 (4%)
Volvo 2 35 (0.5%) 3 (0.4%) 13 (1%)
Other*** 43 (3%)
Total 144 225 218 88 112 221 1,008 719 1,229
*Percentages in parentheses represent percentage of column total.
**In the analysis that follows, we exclude reviews of 5 Volkswagen/Audi diesels alleged to be in
violation of emissions standards.
***Other category for fueleconomy.gov includes Aston Martin (7), Bugatti (1), BYD (1), Lamborghini (7),
Lotus (4), Maserati (6), McLaren (3), Mobility Ventures LLC (2), Pagani (1), Roush (7), SRT (1), and Tesla Motors
(3).
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Table 3. Reviews by Vehicle Class; compared with fueleconomy.gov counts*
Vehicle Class
Subcompact Cars
Minicompact Cars
Compact Cars
Two Sealers
Midsize Cars
Large Cars
Small Station Wagons
Midsize Station Wagons
Passenger Vans
Minivans
Small SUVs
Standard SUVs
Small Pickup Trucks
Standard Pickup Trucks
Not Recorded
Other***
Total
Final
Review
Count
79
13
173
81
229
87
26
8
1
15
143
89
1
41
22
1,008
(8%)
(1%)
(17%)
(8%)
(23%)
(9%)
(3%)
(1%)
(0.1%)
(1%)
(14%)
(9%)
(0.1%)
(4%)
(2%)
Matched with fueleconomy.gov
Tech Data** Count
68
12
126
52
147
71
22
8
15
104
69
7
18
719
(9%)
(2%)
(18%)
(7%)
(20%)
(10%)
(3%)
(1%)
(2%)
(14%)
(10%)
(1%)
(3%)
101
52
201
93
215
104
36
4
16
14
179
116
14
54
30
1,229
(8%)
(4%)
(16%)
(8%)
(17%)
(8%)
(3%)
(0.3%)
(1%)
(1%)
(15%)
(9%)
(1%)
(4%)
(2%)
*Percentages in parentheses represent percentage of column total.
** Vehicles with enough trim-specific information to link to a database that identifies which
technologies are on which vehicles
***Other category for fueleconomy.gov contains "Special Purpose Vehicle 2WD", "Special Purpose
Vehicle 4WD", and Cargo Vans.
When analyzing each review, we coded for technologies (e.g., high-speed automatic
transmissions) most likely to affect the requirements for reduced GHG emissions. The list of
technologies came from reviewing the technologies proposed for compliance purposes in EPA
and DOT (2010 and 2012), as well as professional engineering judgment. In addition, we coded
for reviews of operational characteristics such as acceleration, handling, drivability, noise, and
comfort. This allows us to search for patterns in negative (or positive) operational reviews
conditional on mentions of a specific technology, which could suggest the presence of hidden
costs. Table 4 lists the coded efficiency technologies and operational characteristics considered
in this study.
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Table 4. Efficiency Technology and Operational Characteristics Coded
Efficiency Technology
Operational Characteristics
Parent Hierarchy
Active Air Dam
Active Grille Shutters
Active Ride Height
Electric Assist or Low Drag Brakes
Electronic Power Steering
Lighting - LED
Low Rolling Resistance Tires
Mass Reduction
Passive Aerodynamics
Powertrain
Engine
General Powertrain
Transmission
Charging
Drivability
Acceleration
Braking
Handling
General Drivability
Fuel Economy
Noise
Range
Ride Comfort
Vibration
Coding Level
Active Air Dam
Active Grille Shutters
Active Ride Height
Electric Assist or Low Drag Brakes
Electronic Power Steering
Lighting-LED
Low Rolling Resistance Tires
Mass Reduction
Passive Aerodynamics
Cylinder Deactivation
Diesel
Full Electric
Gasoline Direct Injection (GDI)
General Engine
Hybrid
Plug-in Hybrid Electric
Stop-start
Turbocharged
General Powertrain
Continuously Variable Transmission (CVT)
Dual-clutch Transmission (DCT)
General Transmission
High Speed Automatic
Charging
Acceleration Capability -power-torque
Acceleration feel-smoothness-responsiveness
General Acceleration
Brake Feel-responsiveness
General Braking
Stopping Ability
Cornering Ability -grip-balance-body control
General Handling
Steering Feel-controllability -responsiveness
General Drivability
Fuel Economy
General Noise
Interior Noise
Powertrain Noise
Tire-road Noise
Wind Noise
Range
Ride Comfort
Chassis Vibration
General Vibration
Powertrain Vibration
10
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Each review was coded for all mentions of these technologies and operational
characteristics. For instance, consider the following quote from a review: "We like the effortless
power and the smooth transmission, but the auto start/stop system has more delay than some, the
throttle can be a bit on the jumpy side and the light steering is disconcerting." (Edmunds 2014).
The "smooth transmission," elsewhere identified as a 7-speed automatic, was coded as positive
for high-speed automatic transmission; the stop/start system, having "more delay than some,"
was coded as negative. In addition, "effortless power" was coded as positive for acceleration
capability, while the "disconcerting" steering was coded as negative for steering feel.
To conduct the coding, an adjudicator trained two coders to recognize the technologies
and characteristics and their synonyms. As part of the training, the coders were given the same
reviews to code, to check for inter-coder reliability (to ensure replicability of the results). At the
end of the training, the coders reached above 90% agreement and a Cohen's Kappa coefficient of
0.6 (fair agreement), again followed by code by code review and debriefing. After the training,
we continued with independent learning and assessment until the coders reached above 90%
agreement and a Cohen's Kappa coefficient of 0.8 (where 0.75 is considered "excellent
agreement"). The coding operation officially started after that. The coders examined reviews for
mentions of the technologies and operational characteristics, and then, in context, evaluated
whether the reviewers spoke positively, negatively, or neutrally about them. Checks on inter-
coder reliability were conducted regularly to ensure quality.
We coded a total of 1,023 auto reviews (1,008 after data cleaning) from the six websites
for model year 2014 vehicles, representing 36 manufacturers and 14 official vehicle class
categories (using the classification system of the website fueleconomy.gov). Because each
review had multiple individual codes (e.g., for engine and transmission), the total number of
individual efficiency technology codes is 3,535, or about 3.5 codes per review. The total number
of operational characteristics coded was 12,623, or 12.6 codes per review. In terms of publication
dates, 43% of the auto reviews were published in 2013, while the rest were published in 2014
(26%) or no dates were recorded (31%).3
Table 5 presents counts of individual codes for vehicle technologies, where any one
review may have multiple codes covering the same or different technologies represented in the
vehicle. For every technology, the number of positive codes exceeds the number of negative
codes. In the aggregate, 71 percent of the codes for technologies are positive, compared to 13
percent neutral and 16 percent negative. At face value, this result suggests that the new
technologies are generally being received positively. However, this representation of the results
could possibly be due to positive reviews having multiple references, while negative reviews get
fewer mentions.
Table 6 addresses this concern by summarizing the results when the results are
aggregated to individual reviews. If an item to be coded was mentioned multiple times in a
review, then its treatment depends on whether it always was coded the same way. If, for
example, all the codes are positive, then, at the review level, it is listed once in the positive
column. If, on the other hand, it is mentioned in both a positive and a negative way, then it gets
listed twice - once for positive, and once for negative. This approach gives slightly more weight
3 Many MY2014 vehicles were available to professional auto reviewers, and even to the general public, in
2013.
11
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Draft - Subject to Revision
to mixed reviews, perhaps the opposite bias from the code-level analysis. It, nevertheless, shows
the same pattern: the positive reviews outweigh the negative reviews for all fuel-saving
technologies. In the aggregate, reviews with mentions of the technologies have positive
evaluations 68 percent of the time; neutral evaluations 16 percent; and negative evaluations 16
percent of the time. This result also suggests that it is possible, for any of these technologies, to
implement them in ways that auto reviewers find favorable.
Table 5: Total number of positive, negative, and neutral codes by efficiency technology
Parent Hierarchy
Active Air Dam
Active Grille Shutters
Active Ride Height
Electric Assist/Low Drag Brakes
Electronic power steering
Lighting - LED
Low Rolling Resistance Tires
Mass Reduction
Passive Aerodynamics
Powertrain
Engine
General Powertrain
Transmission
Coding Level
Active Air Dam
Active Grille Shutters
Active Ride Height
Electric Assist/Low Drag
Brakes
Electronic Power Steering
Lighting-LED
Low Rolling Resistance Tires
Mass Reduction
Passive Aerodynamics
Cylinder Deactivation
Diesel
Full Electric
GDI
General Engine
Hybrid
Plug-In Hybrid Electric
Stop-Start
Turbocharged
General Powertrain
CVT
DCT
General Transmission
High Speed Automatic
Total
Negative
-
-
-
1
51
1
4
-
4
1
13
4
7
154
28
7
15
23
13
57
27
47
117
574
-
-
-
13%
23%
4%
24%
-
10%
3%
9%
11%
9%
15%
19%
13%
27%
7%
11%
31%
25%
22%
19%
16%
Neutral
-
-
1
3
43
2
5
12
7
4
11
7
7
112
13
6
8
25
19
31
12
28
101
457
-
-
33%
38%
19%
9%
29%
13%
17%
10%
8%
20%
9%
11%
9%
11%
14%
8%
16%
17%
11%
13%
17%
13%
Positive
6
1
2
4
129
20
8
80
30
35
122
24
63
740
104
42
33
285
90
97
67
134
388
2,504
100%
100%
67%
50%
58%
87%
47%
87%
73%
88%
84%
69%
82%
74%
72%
76%
59%
86%
74%
52%
63%
64%
64%
71%
Total
6
1
3
8
223
23
17
92
41
40
146
35
77
1,006
145
55
56
333
122
185
106
209
606
3,535
*These counts exclude reviews of 5 Volkswagen/Audi diesels alleged to be in violation of emissions standards.
12
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Draft - Subject to Revision
Table 6: Number of positive, negative, and neutral evaluations by auto review
Parent Hierarchy
Active Air Dam
Active Grille Shutters
Active Ride Height
Electric Assist or Low Drag
Brakes
Electronic power steering
Lighting - LED
Low Rolling Resistance Tires
Mass Reduction
Passive Aerodynamics
Powertrain
Engine
General Powertrain
Transmission
Coding Level
Active Air Dam
Active Grille Shutters
Active Ride Height
Electric Assist Or Low Drag
Brakes
Electronic Power Steering
Lighting-LED
Low Rolling Resistance Tires
Mass Reduction
Passive Aerodynamics
Cylinder Deactivation
Diesel
Full Electric
GDI
General Engine
Hybrid
Plug-In Hybrid Electric
Stop-Start
Turbocharged
General Powertrain
CVT
DCT
General Transmission
High Speed Automatic
Total
Negative
-
-
-
1
45
1
4
-
4
1
7
2
6
104
16
4
14
20
8
35
16
30
60
378
-
-
-
14%
22%
5%
24%
-
10%
3%
12%
9%
9%
16%
23%
14%
27%
9%
8%
31%
24%
18%
14%
16%
Neutral
-
-
1
3
42
2
5
9
7
4
9
6
6
95
10
6
7
23
19
20
10
26
81
391
-
-
33%
43%
20%
10%
29%
12%
18%
11%
15%
27%
9%
15%
14%
21%
14%
10%
18%
18%
15%
16%
20%
16%
Positive
6
1
2
3
121
17
8
65
29
30
44
14
54
443
45
18
30
180
78
57
42
108
273
1,668
100%
100%
67%
43%
58%
85%
47%
88%
73%
86%
73%
64%
82%
69%
63%
64%
59%
81%
74%
51%
62%
66%
66%
68%
Total
6
1
o
6
7
208
20
17
74
40
35
60
22
66
642
71
28
51
223
105
112
68
164
414
2,437
*These counts exclude reviews of 5 Volkswagen/Audi diesels alleged to be in violation of emissions standards.
Because the results by codes and by reviews are similar, the following discussion focuses
on the results by review.
The mentions of the technologies in the reviews are not very frequent. As noted above,
there are about 3.5 codes of any of these technologies per review; excluding General Engine,
General Powertrain, and General Transmission (which are not specific fuel-saving technologies),
there are about 2.2 codes of fuel-saving technologies per review. The most mentioned fuel-
saving technologies are high-speed automatic transmissions, turbocharging, electronic power
steering (EPS), and continuously variable transmissions (CVTs); other technologies are
mentioned in fewer than 10 percent of the reviews. It is important to note that absence of
mention of a technology in a review does not mean that the technology is absent; it means that
the reviewer did not comment on it. It seems plausible that reviewers would notice and comment
on undesirable features; a lack of mention when a technology is present may then be interpreted
as an absence of a hidden cost. If so, the positive and neutral codings may under-represent the
true effect of the technology. To examine this question, as discussed above, we were able to
match 71% of the vehicles reviewed with technology data.
The technologies mentioned most positively in percentage terms include active air dams
(100 percent of 6 reviews), active grille shutters (100 percent of 1 review), mass reduction (88
percent of 74 reviews), cylinder deactivation (86 percent of 35 reviews), LED lights (85 percent
13
-------
Draft - Subject to Revision
of 20 reviews), gasoline direct injection (GDI, 82 percent of 66 reviews), and turbocharging (81
percent of 223 reviews). With the exception of turbocharging, these technologies are mentioned
in less than 10 percent of reviews. The proportion of the reviews that mention one of these
technologies is higher for luxury brands than for standard brands:4 172 out of 403 reviews
(43%) for a luxury brand mention one or more of these technologies, while 162 out of 600
reviews (27%) for a standard brand mention one or more. It is not possible to say whether these
technologies are considered high-end, and thus more suitable for luxury vehicles, or whether
they are being implemented with high quality for these uses.
The technologies with at least 20 percent of negative reviews include continuously
variable transmissions (CVTs, 31 percent of 112 reviews), stop-start (27 percent of 51 reviews),
low rolling resistance tires (24 percent of 17 reviews), dual-clutch transmissions (DCTs) (24
percent of 68 reviews), hybrids (23 percent of 71 reviews), and electronic power steering (EPS,
22 percent of 208 reviews). With the exceptions of CVTs and EPS, these technologies were also
mentioned in less than 10 percent of reviews. These technologies were mentioned in reviews for
luxury brands at close to the same rate as for standard brands: 37% (151 out of 403) of reviews
for luxury brands, and 34% (204 out of 600) reviews for standard brands mentioned one or more
of these technologies. As a group, the proportion of negative reviews is very similar for luxury
(27%) and standard (23%) brands. Unlike the better-reviewed technologies, these technologies
appear not to be over-represented in the luxury segment. Even the worst reviewed of these
technologies (CVTs), though, still had 51 percent positive mentions and 18 percent neutral
mentions.
Table 7 shows the percent of negative reviews for both technologies and operational
characteristics by manufacturer. As it shows, there is a great deal of variation, for both
categories, in the proportion of negative reviews. Bentley, Chrysler, and Rolls Royce have no
negative evaluations of efficiency technologies (out of a total of 39 coded technologies), while
Fiat had 53 percent of 15 coded technologies evaluated as negative. For operational
characteristics, Acura, Audi, Bentley, Ram, Rolls Royce, and Smart had less than 10 percent of
the characteristics evaluated negatively (Smart had only 1, positive, code); Mitsubishi had
negative evaluations of 56 percent of its codes for operational characteristics. The correlation
between these percentages is 0.80: companies that are well rated on operational characteristics
also appear to implement efficiency technologies positively.
4 Luxury brands are here defined as Acura, Audi, Bentley, BMW, Cadillac, Ferrari, Infiniti, Jaguar, Land
Rover, Lexus, Lincoln, Mercedes, Porsche, Rolls Royce, and Volvo. These covered 403 of the 1003 reviews.
14
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Draft - Subject to Revision
Table 7: Percent Negative Reviews of Efficiency Technologies and Operational Characteristics,
by Manufacturer
Make
Acura
Audi
Bentley
BMW
Buick
Cadillac
Chevrolet
Chrysler
Dodge
Ferrari
Fiat
Ford
GMC
Honda
Hyundai
Infmiti
Jaguar
Jeep
% Negative
Tech Reviews
6.9%
5.9%
0.0%
9.8%
27.3%
9.2%
14.0%
0.0%
12.5%
9.5%
53.3%
16.4%
14.3%
7.7%
25.5%
28.1%
3.8%
26.9%
% Negative
Operational
Characteristics
Reviews
8.5%
9.3%
6.1%
11.0%
22.3%
12.2%
14.8%
10.0%
20.6%
10.4%
39.1%
15.6%
18.2%
13.7%
22.1%
19.7%
11.2%
25.1%
Make
Kia
Land Rover
Lexus
Lincoln
Mazda
Mercedes
Mini Cooper
Mitsubishi
Nissan
Porsche
Ram
Rolls Royce
Scion
Smart
Subaru
Toyota
Volkswagen
Volvo
% Negative
Tech Reviews
13.3%
4.5%
26.4%
38.5%
8.9%
14.1%
22.7%
39.1%
34.1%
10.9%
11.1%
0.0%
16.7%
—
32.8%
14.0%
13.2%
40.0%
% Negative
Operational
Characteristics
Reviews
15.0%
13.4%
21.6%
24.4%
13.6%
13.9%
20.0%
56.3%
25.8%
12.5%
6.5%
4.6%
36.4%
0.0%
21.8%
22.5%
15.4%
30.0%
For further assessment of the relationship between vehicle technologies and hidden costs,
we examined the relationship between evaluations of operational characteristics - specifically,
the negative evaluations - and the technologies.
Table 8 and Table 9 provide the fraction of reviews where an efficiency technology is
mentioned (Table 8) or appears in the technology data (Table 9) with negative operational
characteristics. For comparison, these tables include the fraction of reviews where the efficiency
technology is not mentioned (Table 8) or not included (Table 9) with negative evaluations of that
characteristic, and whether those proportions are statistically different based on simple t-tests of
differences in means. For instance, in Table 8, for the subset of reviews that mention CVT (83
reviews), 40% of those reviews also negatively review the acceleration capability. This differs by
+26 percentage points from the subset of reviews that do not mention CVT, i.e. 14% of reviews
that do not mention CVT also give a negative review of acceleration capability. This difference
is statistically significant at the 1% level base on the simple t-test. This result is nearly identical
to the analogous result in Table 9 using the tech data for presence of CVT. In that case, 41% of
vehicles with CVT get a negative review on acceleration capability compared to 14% of vehicles
without CVT, a difference which is again significant at the 1% level.
15
-------
Draft - Subject to Revision
For many other technologies the differences are negative, i.e., vehicles with the
technologies have fewer negative reviews. In Table 8, for example, vehicles with mentions of
stop-start technology have a negative rating on acceleration capability 6% of the time, compared
to 17% of cars without stop-start technology, for a difference of-11%. This difference is also
significant at the 1% level based on the simple t-test. Once again, this result is very close to the
result using the tech data from Table 9 where 8% of vehicles with stop-start receive a negative
rating on acceleration capability, compared to 18% of vehicles without stop-start.
As noted above, we do not have tech data for all of the coded efficiency technologies in
our review database. Nonetheless, the results are generally similar for technologies that are
represented in both Table 8 and Table 9.
16
-------
Draft - Subject to Revision
Table 8: Share of reviews with negative operational reviews conditional on efficiency technology
Active Air Dam (N=6)
Active Grille Shutters
(N=l)
Active Ride Height
(N=3)
Low Resistance Tires
(N=14)
Electronic Power
Steering (N=193)
Turbocharged
(N=195)
GDI (N=62)
Cylinder Deactivation
(N=35)
Diesel (N=47)
Hybrid (N=54)
Plug-In Hybrid
Electric (N=l 8)
Full Electric (N= 18)
Stop-Start (N=49)
General Engine
(N=547)
High Speed
Automatic (N=351)
CVT (N=83)
DCT (N=54)
General Transmission
(N=138)
General Powertrain
(N=101)
Elec Assist Or Low
Drag Brakes (N=6)
Lighting-LED (N=17)
Mass Reduction
(N=73)
Passive Aerodynamics
(N=38)
8
fe
M
1
&
X
0.00
J5***
0.00
-0.15
0.00
-.15***
0.21
0.07
0.28
j7***
0.14
-0.01
0.13
-0.02
0.17
0.03
0.09
-0.06
0.15
0
0.06
-0.09
0.11
-0.04
0.18
0.04
0.14
0
0.15
0
0.24
.1**
0.15
0
0.17
0.02
0.15
0
0.17
0.02
0.24
0.09
0.10
-0.05
0.11
-0.04
M
1*
II
0 <
0.00
_ 09***
0.00
-0.09
0.00
-.09***
0.29
0.2
0.10
0.01
0.10
0.01
0.02
-.08***
0.00
_.,***
0.04
-0.05
0.09
0
0.11
0.02
0.06
-0.04
0.06
-0.03
0.11
.04**
0.10
0.01
0.14
0.06
0.13
0.04
0.06
-.04*
0.06
-0.04
0.00
-.09***
0.12
0.03
0.07
-0.03
0.08
-0.01
General
Drivability
0.00
j2***
0.00
-0.12
0.00
-.12***
0.21
0.1
0.08
-.05**
0.09
-0.03
0.08
-0.04
0.06
-0.06
0.04
-.08**
0.22
.11*
0.11
0
0.17
0.05
0.10
-0.01
0.14
.05**
0.10
-0.02
0.31
.22***
0.07
-0.04
0.11
-0.01
0.14
0.03
0.00
-.12***
0.24
0.12
0.04
-.08***
0.05
-.07*
on
•g .3
o -3
c c
OK
0.17
0.09
0.00
-0.08
0.00
-.08***
0.07
-0.01
0.05
-.04*
0.04
-.05***
0.03
-.05**
0.03
-.06*
0.00
_ 09***
0.07
-0.01
0.11
0.03
0.06
-0.03
0.06
-0.02
0.09
0.01
0.09
0.01
0.18
.11**
0.11
0.03
0.06
-0.03
0.11
0.03
0.00
-.08***
0.24
0.16
0.04
-.04*
0.05
-0.03
Acceleration
Feel
0.00
-.08***
0.00
-0.08
0.00
-.08***
0.21
0.14
0.08
0
0.08
0.01
0.08
0.01
0.06
-0.02
0.02
-.06**
0.13
0.06
0.00
-.08***
0.22
0.15
0.08
0.01
0.07
-0.01
0.07
-0.02
0.17
.1**
0.07
0
0.09
0.01
0.07
-0.01
0.17
0.09
0.00
-.08***
0.01
_ 07***
0.03
-.05*
Acceleration
Capability
0.00
-.16***
0.00
-0.16
0.33
0.17
0.21
0.05
0.13
-0.04
0.13
-0.04
0.21
0.05
0.20
0.04
0.17
0.01
0.17
0
0.17
0
0.22
0.06
0.06
j j***
0.19
.06***
0.15
-0.03
0.40
.26***
0.17
0
0.17
0.01
0.19
0.03
0.17
0
0.18
0.01
0.10
-.07*
0.08
-.09*
General
Acceleration
0.00
_ 02***
0.00
-0.02
0.00
-.02***
0.07
0.05
0.01
-.02*
0.01
_ 02***
0.00
-.03***
0.00
-.02***
0.02
0
0.02
-0.01
0.06
0.03
0.06
0.03
0.02
0
0.03
0.01
0.01
-.02***
0.02
0
0.02
-0.01
0.04
0.01
0.05
0.03
0.00
-.02***
0.00
_ 02***
0.01
-0.01
0.00
-.02***
Brake Feel
0.00
-.05***
0.00
-0.05
0.00
-.05***
0.07
0.03
0.06
0.02
0.03
-0.02
0.02
-.03*
0.03
-0.02
0.02
-0.03
0.15
.11**
0.11
0.07
0.06
0.01
0.04
-0.01
0.04
-0.01
0.05
0
0.13
.09**
0.06
0.01
0.06
0.01
0.07
0.03
0.00
-.05***
0.00
-.05***
0.07
0.02
0.08
0.03
M
l£
O-T3
& -3
0.00
- 03***
0.00
-0.03
0.00
-.03***
0.07
0.04
0.06
.03*
0.02
-0.01
0.05
0.02
0.11
0.09
0.02
-0.01
0.06
0.03
0.06
0.03
0.06
0.03
0.02
-0.01
0.03
0
0.03
0
0.08
.06*
0.04
0.01
0.03
0
0.05
0.02
0.17
0.14
0.00
- 03***
0.01
-0.02
0.03
0
•a g>
Si
O 03
0.00
_ 02***
0.00
-0.02
0.00
-.02***
0.00
-.02***
0.02
-0.01
0.02
0
0.00
-.02***
0.00
-.02***
0.00
_ 02***
0.06
0.04
0.06
0.04
0.00
-.02***
0.02
0
0.01
-.02**
0.01
-.02**
0.02
0
0.02
0
0.07
.05**
0.01
-0.01
0.00
-.02***
0.00
_ 02***
0.01
-0.01
0.08
0.06
lire-Road
^Joise
0.00
_ 07***
0.00
-0.07
0.00
-.07***
0.07
0
0.09
0.03
0.07
0
0.05
-0.02
0.03
-0.04
0.02
-.05**
0.00
-.08***
0.06
-0.02
0.00
-.07***
0.10
0.03
0.09
.04**
0.09
0.03
0.11
0.04
0.15
0.08
0.12
.05*
0.10
0.03
0.00
-.07***
0.24
0.17
0.08
0.01
0.05
-0.02
The top number in each cell is the fraction of reviews with a negative coded statement about the operational
characteristic (column) conditional on also having a coded statement about the efficiency technology (row).
The second number measures the difference with all other reviews that do not have coded statements about
the technology. Significance with 10% (*), 5% (**), and 1% (***) is estimated using t-tests for differences
in means.
17
-------
Draft - Subject to Revision
Table 8 Continued
Active Air Dam (N=6)
Active Grille Shutters
(N=l)
Active Ride Height
(N=3)
Low Resistance Tires
(N=14)
Electronic Power
Steering (N=193)
Turbocharged
(N=195)
GDI (N=62)
Cylinder Deactivation
(N=35)
Diesel (N=47)
Hybrid (N=54)
Plug-In Hybrid
Electric (N=l 8)
Full Electric (N= 18)
Stop-Start (N=49)
General Engine
(N=547)
High Speed
Automatic (N=351)
CVT (N=83)
DCT (N=54)
General Transmission
(N=138)
General Powertrain
(N=101)
Elec Assist Or Low
Drag Brakes (N=6)
Lighting-LED (N=17)
Mass Reduction
(N=73)
Passive Aerodynamics
(N=38)
•§ »
&Z
0.00
-.03***
0.00
-0.03
0.00
- 03***
0.00
- 03***
0.03
0
0.01
-.02**
0.03
0
0.00
- 03***
0.02
-0.01
0.00
-.03***
0.00
- 03***
0.00
- 03***
0.00
-.03***
0.03
0.01
0.03
0.01
0.07
0.05
0.00
-.03***
0.07
.04*
0.05
0.02
0.00
- 03***
0.00
-.03***
0.03
0
0.03
0
° 0
II
0.00
-.02***
0.00
-0.02
0.00
_ Q2***
0.00
_ Q2***
0.00
-.02***
0.01
-0.01
0.02
0
0.00
_ Q2***
0.00
-.02***
0.00
-.02***
0.00
_ Q2***
0.00
_ Q2***
0.00
-.02***
0.02
.02**
0.02
0.01
0.02
0.01
0.04
0.02
0.03
0.02
0.02
0
0.00
_ Q2***
0.18
0.16
0.00
-.02***
0.03
0.01
Powertrain
Moise
0.00
-.15***
0.00
-0.14
0.00
_ j4***
0.21
0.07
0.15
0
0.14
-0.01
0.06
-.09**
0.09
-0.06
0.11
-0.04
0.20
0.06
0.33
0.19
0.11
-0.03
0.12
-0.02
0.14
0
0.14
0
0.37
25***
0.09
-0.05
0.14
0
0.16
0.02
0.17
0.02
0.06
-0.09
0.11
-0.04
0.11
-0.04
1.2
S o
G z
0.00
-.06***
0.00
-0.06
0.00
-.06***
0.14
0.09
0.04
-.03*
0.03
-.04***
0.05
-0.01
0.03
-0.03
0.04
-0.02
0.09
0.04
0.00
-.06***
0.06
0
0.10
0.05
0.06
0.01
0.05
-0.02
0.18
j3***
0.06
0
0.10
.05*
0.15
j***
0.00
-.06***
0.12
0.06
0.04
-0.02
0.05
-0.01
Chassis
Vibration
0.00
-.01***
0.00
-0.01
0.00
-.01***
0.00
-.01***
0.02
0.02
0.01
0
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.01
.01***
0.01
0
0.01
0.01
0.02
0.01
0.02
0.02
0.01
0
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.00
-.01***
Powertrain
Vibration
0.00
-.01***
0.00
-0.01
0.00
-.01***
0.00
-.01***
0.01
0
0.02
0.01
0.00
-.01***
0.03
0.02
0.02
0.01
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.02
0.01
0.02
.01**
0.01
0.01
0.02
0.02
0.02
0.01
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.01
0
0.00
-.01***
General
Vibration
0.00
-.02***
0.00
-0.02
0.00
_ Q2***
0.07
0.05
0.01
-0.01
0.02
0
0.03
0.01
0.03
0.01
0.00
-.02***
0.00
-.02***
0.00
_ Q2***
0.00
_ Q2***
0.04
0.02
0.02
0.01
0.02
0.01
0.04
0.02
0.06
0.04
0.01
-0.01
0.02
0
0.00
_ Q2***
0.00
-.02***
0.03
0.01
0.00
_ Q2***
1
II
rt O
0.17
0.02
0.00
-0.15
0.00
j^***
0.21
0.07
0.13
-0.02
0.12
-0.03
0.19
0.05
0.23
0.08
0.04
-.11***
0.11
-0.04
0.00
j^***
0.17
0.02
0.27
.12*
0.19
.08***
0.19
.06**
0.18
0.04
0.24
0.1
0.18
0.04
0.15
0
0.00
j^***
0.24
0.09
0.18
0.03
0.13
-0.02
Fuel
Economy
0.00
-.16***
0.00
-0.16
0.00
-.16***
0.00
-.16***
0.12
-.05*
0.13
-0.03
0.03
_ j4***
0.06
-.11**
0.06
_.,***
0.17
0.01
0.06
-.11*
0.06
-.11*
0.16
0
0.20
.08***
0.16
0
0.25
j**
0.04
-.13***
0.17
0.01
0.20
0.04
0.00
-.16***
0.12
-0.04
0.03
_14***
0.13
-0.03
OJ
00
(^
0.00
-.01***
0.00
-0.01
0.00
-.01***
0.07
0.07
0.01
0
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.28
.28**
0.11
0.11
0.02
0.01
0.00
-.01**
0.00
-0.01
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.01
0
0.00
-.01***
0.00
-.01***
0.00
-.01***
0.03
0.02
00
c
'on
S
O
0.00
0*
0.00
0
0.00
0*
0.00
0*
0.00
0*
0.00
0*
0.00
0*
0.00
0*
0.00
0*
0.00
0*
0.11
0.11
0.06
0.05
0.00
0*
0.00
0
0.00
0*
0.00
0*
0.00
0*
0.01
0
0.00
0*
0.00
0*
0.00
0*
0.01
0.01
0.00
0*
The top number in each cell is the fraction of reviews with a negative coded statement about the operational
characteristic (column) conditional on also having a coded statement about the efficiency technology (row).
The second number measures the difference with all other reviews that do not have coded statements about
the technology. Significance with 10% (*), 5% (**), and 1% (***) is estimated using t-tests for differences
in means.
18
-------
Draft - Subject to Revision
Table 9: Share of reviews with negative operational reviews conditional on efficiency technology
using Tech Data
Low Resistance Tires
(N=31)
Diesel (N=38)
Electronic Power
Steering (N=532)
Full Electric (N=8)
GDI (N=424)
Hybrid (N=45)
Plug-In Hybrid
Electric (N=17)
Cylinder Deactivation
(N=58)
Stop-Start (N=130)
Turbocharged
(N=238)
CVT (N=54)
DCT (N=67)
High Speed
Automatic (N=401)
8
fe
M
1
&
X
0.23
0.09
0.13
-0.01
0.16
.05*
0.13
-0.02
0.13
-0.03
0.20
0.06
0.06
-0.09
0.14
-0.01
0.14
-0.01
0.15
0.01
0.22
0.09
0.13
-0.01
0.13
-0.02
M
1*
II
0 <
0.13
0.04
0.00
_ 09***
0.09
0.01
0.00
-.09***
0.08
-0.02
0.09
0
0.18
0.09
0.05
-0.04
0.06
-0.03
0.06
-.03*
0.17
0.09
0.06
-0.03
0.09
0.02
General
Drivability
0.16
0.06
0.00
j j***
0.10
-0.01
0.00
_.,***
0.06
_.,***
0.22
.13*
0.18
0.08
0.05
-.06*
0.04
-.08***
0.07
-.05**
0.26
.17***
0.10
0
0.08
-.06**
General
Handling
0.13
0.05
0.00
-.08***
0.09
.03*
0.00
-.08***
0.05
-.07***
0.07
-0.01
0.18
0.1
0.10
0.03
0.03
-.06***
0.05
-.04**
0.20
.13**
0.06
-0.02
0.06
-0.03
Acceleration
Feel
0.06
-0.01
0.03
-0.05
0.07
-0.01
0.13
0.05
0.06
-0.02
0.09
0.02
0.06
-0.01
0.03
-0.04
0.08
0.02
0.08
0.01
0.15
.08*
0.09
0.02
0.05
-.04**
Acceleration
Capability
0.19
0.04
0.13
-0.03
0.18
.07**
0.13
-0.03
0.12
-.11***
0.27
12*
0.18
0.02
0.07
j***
0.08
_.,***
0.11
-.07**
0.41
.27***
0.13
-0.03
0.12
_ 09***
General
Acceleration
0.03
0
0.00
- 03***
0.03
0.01
0.00
-.03***
0.02
-.03*
0.02
-0.01
0.00
- 03***
0.00
- 03***
0.00
-.04***
0.03
-0.01
0.06
0.03
0.01
-0.02
0.02
-0.01
Brake Feel
0.03
-0.02
0.00
-.06***
0.06
0.02
0.00
-.05***
0.04
-.04**
0.22
.18***
0.00
-.05***
0.03
-0.02
0.03
-0.03
0.03
-.04**
0.06
0
0.03
-0.03
0.05
-0.01
M
l£
O-T3
& -3
GO <,
0.10
0.06
0.03
-0.01
0.05
.03***
0.00
-.04***
0.03
-0.01
0.07
0.03
0.06
0.02
0.07
0.04
0.02
-.03*
0.02
-.02*
0.09
0.06
0.03
-0.01
0.03
-0.01
•a g>
Si
o m
0.03
0.01
0.00
_ 02***
0.03
.02**
0.13
0.1
0.02
-0.01
0.07
0.05
0.00
_ 02***
0.02
-0.01
0.01
-.02*
0.03
0
0.02
0
0.04
0.02
0.01
-.03**
Tire-Road
Noise
0.03
-0.04
0.03
-.05*
0.08
0.03
0.00
-.07***
0.06
-.04*
0.02
-.05**
0.06
-0.01
0.09
0.01
0.04
-.04**
0.05
-0.03
0.07
0
0.12
0.05
0.07
-0.01
The top number in each cell is the fraction of reviews with a negative coded statement about the
operational characteristic (column) conditional on the presence of the efficiency technology (row) as
reported in the matched Tech Data. The second number measures the difference with all other reviews that
Tech Data report do not have the technology. Significance with 10% (*), 5% (**), and 1% (***) is estimated
using t-tests for differences in means.
19
-------
Draft - Subject to Revision
Table 9 Continued
Low Resistance Tires
(N=31)
Diesel (N=38)
Electronic Power
Steering (N=532)
Full Electric (N=8)
GDI (N=424)
Hybrid (N=45)
Plug-In Hybrid
Electric (N=17)
Cylinder Deactivation
(N=58)
Stop-Start (N=130)
Turbocharged
(N=238)
CVT (N-54)
DCT (N-67)
High Speed
Automatic (N=401)
1
13
£
0.03
0
0.03
-0.01
0.04
.03**
0.00
-.04***
0.03
-0.02
0.00
-.04***
0.00
.04***
0.03
0
0.02
-.02*
0.01
-.03***
0.07
0.04
0.01
-0.02
0.03
-0.02
1
g
c
0.03
0.02
0.00
_ Q2***
0.01
-0.01
0.00
-.02***
0.01
-0.01
0.00
-.02***
0.00
_ Q2***
0.02
0
0.00
_ Q2***
0.00
-.02**
0.02
0
0.01
0
0.01
0
'§ ra
Is 'o
s^
0.19
0.05
0.11
-0.04
0.16
0.04
0.00
-.15***
0.09
-.13***
0.18
0.03
0.29
0.15
0.10
-0.05
0.04
-.13***
0.11
-.05*
0.39
.26***
0.15
0
0.11
-.08***
1
~3
§
O
0.06
0
0.05
-0.01
0.07
0.02
0.00
-.06***
0.04
-.05**
0.07
0
0.00
_ 07***
0.05
-0.01
0.05
-0.02
0.05
-0.03
0.15
.09*
0.06
0
0.05
-.03*
.2 o
O
o>
0.00
-.01**
0.00
-.01**
0.01
-0.01
0.00
-.01**
0.00
-0.01
0.00
-.01**
0.00
-.01**
0.00
-.01**
0.00
-.01**
0.00
-.01**
0.02
0.01
0.01
0.01
0.01
0
.5 a
g 2
Is J
&>
0.00
-.01***
0.03
0.02
0.01
0
0.00
-.01***
0.01
-0.01
0.00
-.01***
0.00
-.01***
0.02
0.01
0.01
0
0.01
0
0.04
0.03
0.00
-.01***
0.01
0
1-1
g g
o>
0.00
_ Q2***
0.00
_ Q2***
0.02
0.01
0.00
-.02***
0.02
-0.01
0.00
-.02***
0.00
_ Q2***
0.00
_ Q2***
0.02
-0.01
0.03
0.01
0.07
0.06
0.04
0.03
0.01
-0.01
t
1
o
u
-o
2
0.03
-.13***
0.03
-.13***
0.15
-0.01
0.00
-.15***
0.14
-0.02
0.11
-0.04
0.06
-0.1
0.17
0.02
0.15
-0.01
0.12
-.05*
0.17
0.01
0.31
.18***
0.14
-0.03
o
g
&
1
0.06
1**
0.08
-.09*
0.14
-.08**
0.00
-.16***
0.11
-.11***
0.20
0.04
0.06
-0.1
0.07
j***
0.10
-.07**
0.11
-.08***
0.24
0.09
0.09
-.08**
0.17
0.02
0
§
0.03
0.02
0.00
-.01**
0.01
0
0.00
-.01**
0.00
-0.01
0.00
-.01**
0.24
.23**
0.00
-.01**
0.01
0
0.00
-0.01
0.00
-.01**
0.00
-.01**
0.00
-0.01
a
&
6
0.10
.1*
0.00
0*
0.01
.01*
0.13
0.12
0.00
-.01*
0.00
0*
0.12
0.12
0.00
0*
0.00
-.01*
0.00
-.01*
0.00
0*
0.00
0*
0.00
-.01*
The top number in each cell is the fraction of reviews with a negative coded statement about the
operational characteristic (column) conditional on the presence of the efficiency technology (row) as
reported in the matched Tech Data. The second number measures the difference with all other reviews that
Tech Data reports do not have the technology. Significance with 10% (*), 5% (**), and 1% (***) is
estimated using t-tests for differences in means.
The descriptive statistics in Table 8 and Table 9 are essentially conditional sample means.
Although it is tempting to make causal statements based on the differences, we cannot assume an
absence of selection bias. For example, although the results suggest that vehicles with CVTs tend
to have a higher percentage of negative reviews on acceleration capability, it could be that the
same vehicles without CVTs would also generate negative acceleration reviews. In other words,
we cannot rule out the possibility that CVTs have been implemented on vehicles that would have
had, on average, worse acceleration scores anyway. If true, then we would not be able to attribute
differences in the fraction of negative reviews by technology to the existence of the technology
itself.
20
-------
Draft - Subject to Revision
In order to reduce concerns about selection bias, we then estimated a series of linear
probability models5 for each operational characteristic that include fixed effects for make,
vehicle class, and website, as well as vehicle attributes from the linked tech data. Although we
cannot rule out the existence of selection bias using this control strategy either, our assumption is
that the fixed effects and vehicle controls generate improved approximations of the effects of
these technologies. At a minimum, we can use the results to discuss the correlations between
efficiency technologies and vehicle performance conditional on class, make, website and vehicle
attributes.
Regression results for each operational characteristic are presented in Appendix Table
Al-Table A22. We estimate six specifications for each operational characteristic, all of which
include fixed effects for make, vehicle class, and website. For the first two specifications, we
used mentions of the technologies in the reviews as our source of the existence of the
technologies on the vehicles; in the next four, we used the technology data. The regressions
using the technology data are further divided between those that use only the data on the fuel-
saving technologies, and those that include a set of additional vehicle attributes included in the
technology data.6 Finally, these 3 sets of regressions (Coded Tech in Review; Tech Data; Tech
Data plus Vehicle Attributes) are further divided into regressions where only one technology is
included, and regressions where all the technologies are included simultaneously.
This process gives six possibilities for a relationship between each operational
characteristic and each technology. We provide one summary of these findings in Table 10,
which shows, for each combination of an operational characteristic and a technology, whether
any of the six regressions has a statistically significant coefficient on that relationship, and
whether the sign of the effect is consistent across the significant results. A positive coefficient
("+" in Table 10) indicates that the presence of the technology is associated with an increase in
the likelihood of a negative review on the characteristic - that is, a hidden cost. A negative
coefficient ("-" in Table 10), in contrast, signals the possibility of a hidden benefit, a positive
relationship between a technology and the characteristic.7
5 As robustness checks, we ran the same sets of regressions using logit and probit specifications. We are
still reviewing those results.
6 Included vehicle attributes include horsepower, torque, number of cylinders, engine displacement, number
of doors, length, width, height, wheelbase, footprint, and curb weight.
7 For some technologies, it may be possible to use efficiency gains either to reduce GHG emissions or to
enhance othervehicle characteristics, such as acceleration (e.g., Klier and Linn 2015). If so, then the hidden benefits
may reflect a decision to implement technologies for purposes other than, or in addition to, GHG reduction.
21
-------
Draft - Subject to Revision
Table 10: Sign and significance level of statistically significant results from linear probability
model regressions that estimate the probability of negative operational characteristic reviews
conditional on efficiency technology.
Active Air Dam
Active Grille Shutters
Active Ride Height
Low Resistance Tires
Electronic Power Steering
Turbocharged
GDI
Cylinder Deactivation
Diesel
Hybrid
Plug-In Hybrid Electric
Full Electric
Stop-Start
High Speed Automatic
CVT
DCT
Elec Assist / Low Drag Brakes
Lighting-LED
Mass Reduction
Passive Aerodynamics
o
O
O
O
8
<
8
O
m
O
*v5
•
S
H
+*
+**
+**
+*
+*
m
* -*
.***
+**
_*
+*
.***
*
** _# _## _##
+* +***
.**
_## +***
_***
+*
+***
_***
+*
** _*
+***
_# +##
+*
_***
+*
+*
+**
Non-empty table cells indicate that a statistically significant result was obtained in one of the LPM
regressions that estimate the probability of a negative review for the column variable conditional on
technology given by the row. The actual regression results are presented in Appendix Table Al-Table
A22. A "+" indicates a consistent positive effect across regressions with significant results for the
efficiency technology, i.e. the technology is associated with increased probability of a negative review.
Conversely, a "-" indicates a consistent negative effect across regressions with significant results for the
efficiency technology, i.e. the technology is associated with a decreased probability of a negative review.
An "m" indicates mixed positive and negative results across the significant estimates. Asterisks indicate
the level of the most significant result obtained across the different LPM estimates: 10% (*), 5% (**), and
!%(***) levels.
22
-------
Draft - Subject to Revision
Table 10 Continued
1
•
Active Air Dam
Active Grille Shutters
Active Ride Height
Low Resistance Tires
Electronic Power Steering
Turbocharged
GDI
Cylinder Deactivation
Diesel
Hybrid
Plug-In Hybrid Electric
Full Electric
Stop-Start
High Speed Automatic
CVT
DCT
Elec Assist / Low Drag Brakes
Lighting-LED
Mass Reduction
Passive Aerodynamics
+**
_*** _***
+#
_** _*
_* _### _***
+###
+***
+**
_* +***
+***
** _*
Non-empty table cells indicate that a statistically significant result was obtained in one of the
LPM regressions that estimate the probability of a negative review for the column variable conditional on
technology given by the row. The actual regression results are presented in Appendix Table Al-Table
A22. A "+" indicates a consistent positive effect across regressions with significant results for the
efficiency technology, i.e. the technology is associated with increased probability of a negative review.
Conversely, a "-" indicates a consistent negative effect across regressions with significant results for the
efficiency technology, i.e. the technology is associated with a decreased probability of a negative review.
An "m" indicates mixed positive and negative results across the significant estimates. Asterisks indicate
the level of the most significant result obtained across the different LPM estimates: 10% (*), 5% (**), and
!%(***) levels.
23
-------
Draft - Subject to Revision
Perhaps a first observation on the table is that about two-thirds of 440 cells (20
technologies by 22 characteristics) are blank: for a majority of the technology-characteristic
combinations, across all specifications, there is no correlation between the technology and the
characteristic. In some cases, technologies are not expected to affect some of the characteristics:
for instance, LED lights are not expected to affect noise, acceleration, or brake feel. In other
cases, as previously discussed, this observation may be due to selection bias. Manufacturers
choose both how to design vehicles for operational characteristics and what technologies to use
in the vehicles, and other factors not included in the regressions may be correlated with both the
characteristics and the technologies. As a result, the regression may not fully control for omitted
factors. Hence, we describe all these results in terms of correlation rather than causality.
For most cases where a correlation is identified, the technology is associated with a lower
probability of a negative review on the operational characteristic. Thirty-seven table cells (8.4
percent) have a significant positive (bad) result, while 108 cells (24.5 percent) have a significant
negative (good) result, and only 1 (0.2 percent) is mixed. In addition, the presence of a
technology may be correlated with negative effects on some characteristics but positive effects
on others: looking across the rows, all but 3 technologies (CVT, DCT, and cylinder
deactivation) have at least as many negative (good) significant effects as positive (bad) effects; 7
technologies (active air dam, turbocharged, GDI, diesel, electronic assist/low drag brakes, mass
reduction, and passive aerodynamics) show only negative (good) significant effects.
We consider Table 10 to provide a highly sensitive measure of the possibility of hidden
costs: it does not consider consistency across specifications, but rather shows any indication of a
relationship between an operational characteristic and a technology. Table 11 provides the
number of significant coefficients in the regressions based on consistent significance across
specifications. As it shows, statistical significance is not very robust in these regressions: the
number of significant coefficients drops rapidly as consistency across more regressions is sought.
In fact, only 2 cells have significant results across all 6 specifications: diesel has a negative
association with a negative rating for general drivability, and CVT has a positive association
with a negative rating for acceleration capability. As discussed above, these sensitivities may
reflect correlations of observed variables with unobserved variables.
Table 11: Number of Significant Coefficients Conditional on the Number of Specifications with
Significance (out of 440 possible coefficients)
Number of Significant Estimates
Positive Correlations
Negative Correlations
Mixed Correlations
Total
1
37
108
1
146
2
21
71
1
93
3
12
24
0
36
4
7
17
0
24
5
2
4
0
6
6
1
1
0
2
The analyses above have focused on negative evaluations of operational characteristics - hidden
costs - as the key variables of interest. It is possible that some of these negative evaluations of
characteristics are due, not to the existence of the technology, but rather to the way that the
technology is implemented. Perhaps, for instance, a badly implemented CVT is associated with
negative acceleration capability, but a well implemented CVT may not have this effect. Table 12
explores this question by considering the relationship between the rating of a technology with the
24
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ratings of the operational characteristics.8 Each cell summarizes 22 regressions of each
operational characteristic on a technology, where the dependent variable is again a dummy
variable for a negative review of each operational characteristic. The regressions use the coded
review data to control for "any mention" of all other technologies as well as make, website, and
class fixed effects. The table reports estimates for 4 separate groups of regressions with the only
differences being the rating represented by the dummy variable for the row technology. For
instance, the presence of CVTs (All Mentions) is associated with a negative rating on four
operational characteristics. The next column, Negative Tech, shows that negative evaluations of
CVTs are associated with negative ratings for seven operational characteristics. In other words,
there are more negative evaluations of operational characteristics when CVTs are rated
negatively than when they are merely present. This pattern generalizes: technologies that are
evaluated negatively are more likely to be associated with negative evaluations of operational
characteristics than when the technologies are evaluated neutrally or positively, or are just
present. It is possible that poor implementation may be contributing to negative evaluations of
operational characteristics; positive or neutral evaluations of the technologies do not have the
same adverse effects on operational characteristics.
8 This analysis uses only the content analysis data, because it contains evaluations of the technologies. The
technology database does not include evaluations of the technologies. This analysis uses the regressions with all
technologies included.
25
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Draft - Subject to Revision
Table 12: Relationship of Rating of Technologies with Rating of Operational Characteristics
Active Air Dam
Active Grille Shutters
Active Ride Height
Low Resistance Tires
Electronic Power Steering
Turbocharged
GDI
Cylinder Deactivation
Diesel
Hybrid
Plug-In Hybrid Electric
Full Electric
Stop-Start
High Speed Automatic Transmission
CVT
DCT
Elec Assist Or Low Drag Brakes
Lighting-LED
Mass Reduction
Passive Aerodynamics
All
Mentions
1
1
1
4
Negative
Tech
2
1
2
1
2
2
3
1
7
7
1
3
2
1
Neutral
Tech
1
1
Positive
Tech
1
Each row summarizes 4 groups of regressions, where each operational characteristic is regressed on a dummy
variable for the presence of a negative, neutral, positive, or any mention (specified by the column) of the row
technology. The dependent variables are again dummy variables for negative reviews of each operational
characteristic. The regressions use the coded review data to control for "any mention" of all other technologies as
well as make, website, and class fixed effects.
In sum, our analyses find scant consistent evidence of hidden costs of emissions-reducing
technologies. Each technology is reviewed positively more often than it is reviewed negatively;
this finding suggests that implementation of the technologies, and not just the technologies
themselves, affects the existence of hidden costs. Correlations between the existence of the
technologies and operational characteristics often suggest that the technologies reduce the
probability of negative reviews of the characteristics, and are not robust to alternative
specifications. Negative evaluations of operational characteristics appear to be more common
when the technologies are evaluated negatively than when they are merely present, another
suggestion that poor implementation may be the primary source of hidden costs.
26
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Draft - Subject to Revision
of this
Content analysis as a method involves some degree of subjectivity; two readers of the
same review may come to different conclusions about the reviewer's responses. We believe this
concern is unlikely to be significant. First, as noted above, we conducted significant training of
the coders, including testing for (and achieving) inter-coder reliability throughout the coding
process. Secondly, auto reviewers have opinions, and are not expected to be shy or misleading
about their views; although their language may be colorful, the sentiment is generally clear. We
believe the data to be of high quality.
A notable characteristic of this work is that the analysis captures the technologies
mentioned in auto reviews. One result is that biases in the data may arise because the counts of
reviews for models are not proportional to vehicle sales. On the other hand, the proportions of
reviews by make are similar to the proportions of vehicles offered for sale by make; this
observation suggests that the reviews may be more representative of offerings. The data suggest
that luxury vehicles are reviewed more than their representation in vehicle sales. In addition, it
seems plausible that auto reviewers are more likely to test-drive vehicles that have undergone a
significant redesign. Because redesigned vehicles are more likely to incorporate new
technologies than vehicles that have not been redesigned, the data may over-represent the
presence of these new technologies in the MY 2014 market. They may also emphasize the status
of the new technologies; given the positive nature of the response, it suggests that automakers are
generally doing well with these technologies, and it is reasonable to think that they will only do
better in the future with them.
This study relies on the opinions of professional auto reviewers. People who buy new
vehicles may differ in their responses to these new technologies; if the public tends to be harsher
critics than the reviewers, then these results may understate negative consumer response. As
mentioned above, though, we expect professional auto reviewers, as experts, to be aware of
vehicle characteristics and technologies more than the general public. If so, then this study may
underestimate neutral or positive responses from the general public.
As discussed above, our data are not sufficient to identify causality for the effects of the
technologies on vehicles' operational characteristics. It is possible that some technologies show
adverse (or beneficial) effects on operational characteristics that are generated in part from
selection bias. The ideal experiment would be to compare reviews from vehicles with a given
technology to reviews from otherwise identical vehicles without the technology. This is
generally not possible. Although our strategy controls for important fixed effects and vehicle
attributes, our results may still be vulnerable to selection bias. However, even at the level of
correlation, we find fewer signs of adverse effects from the technologies than neutral or
beneficial effects.
The reviewers' comments are based on test drives of the vehicles. As a result, they are
not designed to look for problems that might arise over longer time horizons, such as with
reliability or maintenance. This study covered new MY 2014 vehicles; it will take several years
before these problems, if any, come to light.
Conclusion
The energy paradox exists if there are technologies whose present net value is positive for
consumers, even taking into account potential hidden costs of the technologies. Engineering
analyses of light-duty vehicles suggest that a number of fuel-saving technologies have positive
present net values for consumers. This study investigates whether these technologies have
27
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Draft - Subject to Revision
hidden costs, by examining professional auto reviewers' responses to these technologies in MY
2014 vehicles. For the technologies included in the study - the primary technologies expected to
be used to reduce vehicle GHG and fuel consumption to meet EPA and DOT standards - we find
scant evidence of hidden costs. For all the technologies, positive mentions outweigh negative
mentions; indeed, negative mentions constitute less than 20 percent of the total. Though we are
unable to demonstrate causality or robustness, we find that the technologies are more likely to be
associated with reducing negative reviews of operational characteristics than with increasing
them. Some evidence suggests that, rather than hidden costs being inherent in the technologies,
the quality of the implementation of the technologies may affect vehicle quality. If so, it is likely
that implementation problems are temporary: automakers appear capable of good
implementation of any of the technologies, and they are likely to address concerns as they arise.
We do not find evidence, then, that hidden costs provide an explanation for the energy paradox
in MY 2014 light-duty vehicles.
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Tables
Table Al: "Steering feel" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.07 -0.02
(0.07) (0.07)
-0.34*** -0.22**
(0.10) (0.09)
-0.18** -0.15*
(0.08) (0.08)
0.09 0.04
(0.11) (0.11)
0.17*** 0.17***
(0.03) (0.04)
-0.00 0.00
(0.03) (0.03)
-0.03 -0.06
(0.05) (0.05)
0.04 0.06
(0.09) (0.10)
-0.07 -0.02
(0.05) (0.05)
0.01 -0.06
(0.05) (0.05)
-0.04 -0.06
(0.07) (0.07)
0.03 0.03
(0.08) (0.09)
0.03 0.03
(0.06) (0.06)
-0.06** -0.07**
(0.03) (0.03)
0.07 0.06
(0.06) (0.06)
0.05 0.03
(0.06) (0.06)
0.08 0.05
(0.17) (0.15)
-0.01 -0.02
(0.11) (0.11)
-0.03 -0.05
(0.04) (0.04)
-0.05 -0.03
(0.06) (0.05)
1003
0.09
Tech Data
Single All tech
0.11 0.11
(0.09) (0.09)
-0.00 0.00
(0.04) (0.05)
0.06 0.09
(0.04) (0.05)
-0.01 -0.05
(0.04) (0.05)
0.06 0.08
(0.07) (0.07)
-0.02 -0.04
(0.07) (0.08)
0.03 0.02
(0.06) (0.07)
-0.12 -0.14*
(0.07) (0.08)
0.08 0.02
(0.12) (0.12)
0.02 0.03
(0.06) (0.06)
-0.05 -0.04
(0.04) (0.05)
0.08 0.06
(0.07) (0.08)
0.03 0.01
(0.05) (0.06)
718
0.06
Tech Data plus vehicle
attributes
Single All tech
0.16 0.18
(0.11) (0.11)
-0.07 -0.06
(0.05) (0.05)
0.06 -0.00
(0.07) (0.08)
-0.04 -0.06
(0.05) (0.06)
0.12* 0.11
(0.07) (0.07)
-0.19* -0.22*
(0.11) (0.12)
-0.15*** -0.21***
(0.05) (0.08)
-0.05 -0.20
(0.11) (0.17)
0.00 0.00
O (0
0.00 -0.01
(0.06) (0.06)
-0.04 -0.02
(0.05) (0.05)
0.08 0.00
(0.07) (0.08)
0.08 0.05
(0.06) (0.07)
660
0.05
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Steering Feel" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
32
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Table A2: "Cornering ability" negative review linear probability model regressions on efficiency
technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.08 -0.09
(0.10) (0.10)
-0.19** -0.18**
(0.08) (0.09)
-0.03 -0.02
(0.04) (0.05)
0.25** 0.28**
(0.12) (0.13)
0.02 0.02
(0.03) (0.03)
-0.02 -0.01
(0.03) (0.03)
-0.07*** -0.06**
(0.02) (0.03)
-0.12*** -0.09**
(0.04) (0.04)
-0.03 -0.01
(0.04) (0.04)
-0.03 -0.05
(0.04) (0.05)
0.05 0.05
(0.08) (0.08)
0.00 -0.10
(0.06) (0.07)
-0.05 -0.04
(0.04) (0.04)
-0.03 -0.01
(0.02) (0.02)
0.05 0.06
(0.04) (0.04)
0.02 0.03
(0.04) (0.05)
-0.02 -0.04
(0.03) (0.05)
-0.09 -0.09
(0.10) (0.10)
-0.00 -0.01
(0.03) (0.03)
-0.04 -0.05
(0.05) (0.05)
1003
0.08
Tech Data
Single All tech
-0.01 -0.06
(0.07) (0.08)
-0.05 -0.06
(0.03) (0.04)
-0.03 -0.00
(0.04) (0.05)
-0.01 0.00
(0.04) (0.05)
-0.00 -0.03
(0.04) (0.04)
-0.10*** -0.13***
(0.03) (0.05)
-0.03 0.05
(0.05) (0.05)
0.09 0.15
(0.12) (0.12)
-0.05 0.02
(0.04) (0.06)
0.01 0.03
(0.05) (0.05)
0.02 0.06*
(0.03) (0.03)
0.12** 0.18***
(0.06) (0.06)
-0.01 0.01
(0.04) (0.05)
718
0.03
Tech Data plus vehicle
attributes
Single All tech
0.05 -0.02
(0.10) (0.10)
-0.06 -0.06
(0.04) (0.05)
0.00 -0.01
(0.06) (0.07)
-0.03 -0.03
(0.04) (0.05)
-0.00 -0.01
(0.05) (0.05)
-0.10 -0.12
(0.06) (0.09)
-0.01 0.07
(0.07) (0.08)
0.02 0.01
(0.11) (0.15)
0.00 0.00
O (0
0.07 0.07
(0.05) (0.05)
0.01 0.06
(0.04) (0.04)
0.16** 0.19***
(0.06) (0.06)
0.01 0.04
(0.05) (0.05)
660
0.05
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Cornering Ability" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on
all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
33
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Draft - Subject to Revision
Table A3: "General drivability" negative review linear probability model regressions on efficiency
technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.03 -0.03
(0.08) (0.08)
-0.06 -0.04
(0.06) (0.06)
-0.03 0.00
(0.05) (0.05)
0.12 0.12
(0.12) (0.12)
-0.04 -0.04*
(0.02) (0.02)
-0.01 0.01
(0.03) (0.03)
0.01 0.04
(0.04) (0.05)
-0.06 -0.08
(0.06) (0.07)
-0.06* -0.06*
(0.03) (0.03)
0.09 0.07
(0.06) (0.06)
0.02 0.01
(0.08) (0.09)
0.10 0.04
(0.10) (0.09)
-0.04 -0.03
(0.05) (0.05)
-0.05** -0.03
(0.02) (0.02)
0.14** 0.13**
(0.06) (0.06)
-0.05 -0.05
(0.04) (0.04)
-0.04 -0.05
(0.03) (0.05)
-0.03 -0.05
(0.10) (0.11)
-0.05* -0.04
(0.03) (0.03)
-0.09** -0.06
(0.04) (0.04)
1003
0.09
Tech Data
Single All tech
0.14* 0.10
(0.08) (0.10)
-0.04 -0.06
(0.04) (0.05)
-0.03 0.02
(0.04) (0.05)
-0.06 -0.02
(0.04) (0.04)
-0.01 -0.01
(0.04) (0.04)
-0.10*** -0.10**
(0.03) (0.04)
0.12* 0.15**
(0.06) (0.07)
0.15 0.15
(0.11) (0.13)
-0.06 -0.09
(0.05) (0.08)
-0.05 -0.03
(0.05) (0.05)
-0.04 0.02
(0.03) (0.03)
0.07 0.12
(0.07) (0.08)
-0.00 -0.01
(0.05) (0.05)
718
0.10
Tech Data plus vehicle
attributes
Single All tech
0.22** 0.18
(0.11) (0.12)
-0.11** -0.14***
(0.05) (0.05)
-0.03 -0.06
(0.07) (0.08)
-0.03 0.01
(0.05) (0.05)
-0.02 -0.05
(0.04) (0.04)
-0.17** -0.25***
(0.09) (0.10)
0.08 0.01
(0.10) (0.12)
-0.11 -0.31*
(0.12) (0.16)
0.00 0.00
O (0
-0.00 -0.02
(0.05) (0.05)
-0.02 0.01
(0.03) (0.04)
0.06 0.03
(0.08) (0.08)
-0.03 -0.04
(0.05) (0.06)
660
0.12
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "General Drivability" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on
all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
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Table A4: "General handling" negative review linear probability model regressions on efficiency
technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.27 0.25
(0.18) (0.18)
-0.00 -0.03
(0.04) (0.04)
-0.03 0.02
(0.05) (0.04)
0.03 0.05
(0.08) (0.08)
-0.02 -0.01
(0.02) (0.02)
-0.06** -0.05**
(0.02) (0.02)
-0.02 -0.01
(0.03) (0.03)
-0.04 -0.04
(0.05) (0.06)
-0.09*** -0.07***
(0.03) (0.03)
-0.02 -0.03
(0.04) (0.04)
0.06 0.07
(0.07) (0.09)
-0.01 -0.06
(0.06) (0.06)
-0.05 -0.05
(0.04) (0.04)
-0.01 0.00
(0.02) (0.02)
0.03 0.03
(0.05) (0.05)
0.06 0.05
(0.05) (0.05)
0.01 0.01
(0.04) (0.04)
-0.00 -0.00
(0.09) (0.10)
-0.01 -0.01
(0.03) (0.03)
-0.04 -0.05
(0.04) (0.04)
1003
0.09
Tech Data
Single All tech
0.01 -0.03
(0.07) (0.08)
-0.03 -0.03
(0.03) (0.04)
-0.03 0.00
(0.03) (0.04)
-0.06* -0.07
(0.03) (0.04)
0.10* 0.11*
(0.06) (0.06)
-0.07** -0.03
(0.03) (0.04)
-0.07 -0.05
(0.05) (0.06)
0.11 0.06
(0.11) (0.12)
-0.10** -0.12*
(0.05) (0.07)
-0.05 -0.04
(0.04) (0.04)
-0.03 -0.03
(0.03) (0.03)
0.11* 0.10
(0.07) (0.07)
-0.01 -0.04
(0.04) (0.04)
718
0.04
Tech Data plus vehicle
attributes
Single All tech
0.08 0.05
(0.10) (0.10)
-0.06 -0.05
(0.04) (0.05)
0.03 0.01
(0.07) (0.08)
-0.05 -0.07
(0.04) (0.05)
0.10 0.12*
(0.06) (0.07)
-0.06 -0.03
(0.06) (0.07)
-0.07* -0.08
(0.04) (0.05)
0.09 -0.00
(0.07) (0.11)
0.00 0.00
O (0
-0.01 -0.00
(0.04) (0.04)
-0.04 -0.03
(0.03) (0.04)
0.10 0.07
(0.07) (0.08)
0.02 -0.02
(0.05) (0.05)
660
0.04
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "General Handling" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on
all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
35
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Draft - Subject to Revision
Table A5: "Acceleration feel" negative review linear probability model regressions on efficiency
technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.02 0.03
(0.02) (0.03)
-0.23*** -0.20**
(0.09) (0.09)
-0.17*** -0.13**
(0.06) (0.06)
0.15 0.09
(0.12) (0.10)
0.01 0.00
(0.02) (0.02)
-0.01 0.01
(0.03) (0.03)
-0.00 0.01
(0.03) (0.04)
-0.01 -0.01
(0.03) (0.04)
-0.08** -0.06*
(0.03) (0.04)
0.07 0.04
(0.05) (0.05)
-0.07*** -0.12***
(0.02) (0.04)
0.16 0.15*
(0.10) (0.09)
-0.02 -0.01
(0.05) (0.05)
-0.05*** -0.03*
(0.02) (0.02)
0.08* 0.07
(0.05) (0.05)
0.01 -0.01
(0.04) (0.04)
0.13 0.09
(0.15) (0.13)
-0.16*** -0.17***
(0.04) (0.04)
-0.04** -0.04**
(0.02) (0.02)
-0.06* -0.03
(0.03) (0.03)
1003
0.08
Tech Data
Single All tech
-0.02 -0.05
(0.06) (0.06)
-0.07** -0.07*
(0.03) (0.04)
0.00 0.02
(0.04) (0.04)
-0.02 -0.00
(0.03) (0.04)
-0.01 -0.02
(0.03) (0.03)
-0.08** -0.10*
(0.04) (0.05)
0.02 0.02
(0.05) (0.05)
-0.01 0.00
(0.08) (0.09)
0.03 0.06
(0.12) (0.13)
0.05 0.09
(0.05) (0.05)
-0.05* -0.04
(0.03) (0.03)
0.02 0.04
(0.06) (0.07)
0.05 0.01
(0.05) (0.06)
718
0.01
Tech Data plus vehicle
attributes
Single All tech
-0.05 -0.12
(0.08) (0.09)
-0.04 -0.03
(0.03) (0.04)
-0.03 -0.06
(0.05) (0.05)
-0.06 -0.07
(0.04) (0.04)
-0.01 0.01
(0.03) (0.04)
-0.10 -0.11
(0.08) (0.09)
0.07 0.05
(0.10) (0.10)
-0.26* -0.38**
(0.15) (0.16)
0.00 0.00
O (0
0.14*** 0.14***
(0.05) (0.05)
-0.06* -0.06
(0.04) (0.04)
0.04 0.05
(0.06) (0.07)
0.01 -0.01
(0.06) (0.06)
660
0.03
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Acceleration Feel" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on
all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
36
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Draft - Subject to Revision
Table A6: "Acceleration capability" negative review linear probability model regressions on efficiency
technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.15* -0.15
(0.09) (0.10)
-0.22*** -0.20**
(0.08) (0.09)
0.23 0.20
(0.29) (0.31)
0.02 0.02
(0.12) (0.12)
-0.02 -0.01
(0.03) (0.03)
-0.01 -0.01
(0.03) (0.03)
0.03 0.05
(0.05) (0.05)
0.01 -0.00
(0.07) (0.07)
0.04 0.05
(0.07) (0.07)
-0.02 -0.05
(0.05) (0.06)
0.03 0.02
(0.09) (0.10)
0.08 0.05
(0.11) (0.11)
-0.11*** -0.10**
(0.04) (0.04)
-0.05* -0.03
(0.03) (0.03)
0.21*** 0.21***
(0.06) (0.07)
0.05 0.06
(0.06) (0.06)
-0.01 0.01
(0.17) (0.16)
-0.09 -0.13
(0.09) (0.10)
-0.02 -0.01
(0.04) (0.04)
-0.08 -0.07
(0.05) (0.05)
1003
0.09
Tech Data
Single All tech
0.01 -0.12
(0.09) (0.10)
0.07* 0.08
(0.04) (0.05)
-0.05 -0.01
(0.04) (0.05)
-0.11** -0.13**
(0.04) (0.06)
-0.03 0.01
(0.06) (0.07)
0.02 0.10
(0.07) (0.08)
0.07 0.08
(0.07) (0.08)
0.00 -0.05
(0.10) (0.12)
-0.07 -0.12
(0.13) (0.15)
-0.09* -0.08
(0.05) (0.05)
-0.10** -0.06
(0.04) (0.05)
0.23*** 0.26***
(0.09) (0.09)
-0.02 -0.01
(0.06) (0.07)
718
0.10
Tech Data plus vehicle
attributes
Single All tech
-0.03 -0.15
(0.11) (0.12)
0.02 0.04
(0.05) (0.06)
-0.02 -0.05
(0.09) (0.10)
-0.11* -0.13**
(0.05) (0.06)
-0.03 0.01
(0.07) (0.07)
-0.07 -0.05
(0.11) (0.13)
0.04 0.05
(0.11) (0.13)
0.03 -0.18
(0.11) (0.18)
0.00 0.00
C) (0
-0.15** -0.13**
(0.06) (0.06)
-0.11** -0.08
(0.05) (0.05)
0.18** 0.20**
(0.09) (0.10)
0.04 0.02
(0.07) (0.08)
660
0.10
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Acceleration Capability" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions
on all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported
in parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
37
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Draft - Subject to Revision
Table A7: "General acceleration" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.07 -0.07
(0.06) (0.06)
-0.08 -0.09*
(0.05) (0.05)
0.02* 0.02
(0.01) (0.02)
0.06 0.05
(0.06) (0.07)
-0.00 -0.00
(0.01) (0.01)
-0.02* -0.02
(0.01) (0.01)
-0.01 -0.02*
(0.01) (0.01)
0.01 0.02*
(0.01) (0.01)
0.03 0.03
(0.02) (0.02)
-0.00 -0.01
(0.02) (0.02)
0.04 0.03
(0.06) (0.04)
0.03 0.01
(0.07) (0.07)
0.02 0.02
(0.02) (0.02)
-0.01 -0.01
(0.01) (0.01)
-0.04 -0.04
(0.03) (0.03)
0.01 0.01
(0.02) (0.02)
-0.01 -0.02
(0.01) (0.02)
-0.02 -0.01
(0.02) (0.02)
0.00 0.00
(0.02) (0.02)
-0.01 -0.01
(0.01) (0.01)
1003
0.03
Tech Data
Single All tech
-0.04 0.01
(0.04) (0.05)
0.02 0.02
(0.02) (0.02)
0.04* 0.04
(0.02) (0.03)
0.01 -0.02
(0.02) (0.03)
-0.02 -0.02
(0.01) (0.02)
0.02 0.01
(0.01) (0.02)
-0.03 -0.05
(0.02) (0.03)
-0.03 -0.05
(0.02) (0.04)
-0.08** -0.10
(0.04) (0.06)
-0.04 -0.06*
(0.03) (0.03)
0.03 0.01
(0.03) (0.03)
-0.05 -0.06
(0.04) (0.04)
-0.01 -0.02
(0.03) (0.03)
718
0.04
Tech Data plus vehicle
attributes
Single All tech
-0.03 0.01
(0.07) (0.07)
0.03 0.04
(0.02) (0.02)
0.04 0.05
(0.04) (0.04)
-0.03 -0.04
(0.03) (0.03)
-0.02 -0.01
(0.02) (0.02)
0.06 0.06
(0.04) (0.05)
-0.06** -0.07
(0.03) (0.05)
-0.03 0.03
(0.05) (0.06)
0.00 0.00
O (0
-0.05 -0.04
(0.04) (0.04)
0.04 0.02
(0.03) (0.04)
-0.04 -0.04
(0.04) (0.04)
-0.01 -0.01
(0.03) (0.03)
660
0.06
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "General Acceleration" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions
on all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported
in parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
38
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Draft - Subject to Revision
Table A8: "Brake feel" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.01 0.03
(0.01) (0.02)
-0.03 -0.03
(0.04) (0.05)
-0.02 -0.01
(0.03) (0.04)
0.02 -0.00
(0.07) (0.07)
0.02 0.02
(0.02) (0.02)
-0.02 -0.01
(0.02) (0.02)
-0.00 -0.01
(0.02) (0.02)
0.01 0.01
(0.05) (0.05)
-0.02 -0.01
(0.03) (0.03)
0.10** 0.10*
(0.05) (0.05)
0.09 0.09
(0.08) (0.09)
0.02 -0.00
(0.06) (0.06)
-0.02 -0.02
(0.03) (0.03)
-0.00 0.01
(0.02) (0.02)
0.07 0.06
(0.04) (0.04)
0.00 0.00
(0.03) (0.03)
-0.01 -0.03
(0.02) (0.05)
-0.10*** -0.11***
(0.03) (0.04)
0.03 0.02
(0.03) (0.03)
0.04 0.03
(0.04) (0.04)
1003
0.04
Tech Data
Single All tech
-0.01 -0.01
(0.06) (0.06)
0.01 0.00
(0.03) (0.03)
-0.04* -0.03
(0.02) (0.03)
-0.02 0.00
(0.02) (0.03)
-0.03 -0.02
(0.04) (0.05)
-0.04** -0.04
(0.02) (0.03)
0.18*** 0.18***
(0.06) (0.07)
-0.05 -0.03
(0.04) (0.05)
-0.02 -0.01
(0.03) (0.05)
0.01 0.02
(0.03) (0.04)
-0.01 0.02
(0.03) (0.02)
-0.09* -0.04
(0.05) (0.05)
-0.01 0.00
(0.03) (0.03)
718
0.05
Tech Data plus vehicle
attributes
Single All tech
0.01 -0.01
(0.04) (0.04)
-0.00 -0.03
(0.03) (0.03)
-0.06 -0.07
(0.05) (0.06)
0.00 0.02
(0.03) (0.03)
0.01 -0.01
(0.03) (0.04)
-0.09 -0.11*
(0.06) (0.07)
0.10 0.07
(0.08) (0.10)
0.05 -0.03
(0.07) (0.12)
0.00 0.00
O (0
0.02 0.01
(0.03) (0.04)
0.02 0.02
(0.02) (0.02)
-0.07 -0.05
(0.05) (0.06)
-0.03 -0.02
(0.04) (0.04)
660
0.04
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Brake Feel" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
39
-------
Draft - Subject to Revision
Table A9: "Stopping
ability" negati1
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
^e review linear
Any coded mention of
tech in review
Single All tech
-0.01 -0.01
(0.01) (0.02)
-0.07 -0.05
(0.04) (0.04)
0.01 0.01
(0.02) (0.02)
0.03 0.01
(0.07) (0.07)
0.02 0.02
(0.02) (0.02)
-0.01 -0.00
(0.01) (0.02)
-0.01 -0.01
(0.02) (0.02)
0.04 0.05
(0.05) (0.05)
0.01 0.02
(0.03) (0.03)
0.02 0.00
(0.03) (0.03)
0.02 0.01
(0.05) (0.05)
0.05 0.03
(0.05) (0.06)
-0.00 -0.00
(0.02) (0.02)
-0.03** -0.02
(0.01) (0.01)
0.06* 0.06*
(0.03) (0.03)
0.04 0.03
(0.03) (0.03)
0.10 0.08
(0.16) (0.16)
-0.07** -0.08**
(0.03) (0.03)
-0.03 -0.03
(0.02) (0.02)
-0.01 0.00
(0.03) (0.03)
1003
0.02
)robability model regressions on efficiency technology
Tech Data
Single All tech
0.08 0.07
(0.06) (0.06)
0.00 0.01
(0.02) (0.02)
-0.00 0.00
(0.02) (0.03)
-0.01 -0.01
(0.02) (0.03)
0.05** 0.07***
(0.02) (0.03)
0.00 0.03
(0.03) (0.04)
0.02 0.05
(0.04) (0.04)
-0.02 -0.02
(0.06) (0.05)
-0.01 -0.03
(0.02) (0.04)
-0.03 -0.02
(0.02) (0.02)
-0.02 0.01
(0.02) (0.02)
0.07 0.08**
(0.05) (0.04)
0.05 0.07*
(0.03) (0.04)
718
0.03
Tech Data plus vehicle
attributes
Single All tech
0.09 0.05
(0.08) (0.08)
-0.02 -0.01
(0.02) (0.03)
0.01 0.00
(0.04) (0.04)
-0.02 -0.03
(0.03) (0.04)
0.08*** 0.09***
(0.03) (0.03)
-0.00 0.02
(0.05) (0.06)
-0.00 0.03
(0.02) (0.04)
-0.05 -0.04
(0.05) (0.06)
0.00 0.00
(•) (•)
-0.04 -0.04
(0.03) (0.03)
-0.02 0.01
(0.02) (0.02)
0.08* 0.09**
(0.04) (0.04)
0.07* 0.07*
(0.04) (0.04)
660
0.04
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Stopping Ability" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
40
-------
Draft - Subject to Revision
Table A10: "General braking" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.01 0.02
(0.01) (0.02)
-0.01 -0.01
(0.04) (0.04)
0.01 0.03
(0.02) (0.02)
0.00 -0.01
(0.01) (0.02)
-0.01 -0.01
(0.01) (0.01)
-0.01 -0.00
(0.01) (0.01)
-0.02** -0.01*
(0.01) (0.01)
-0.02 -0.02
(0.02) (0.02)
-0.01 -0.02
(0.01) (0.01)
0.05 0.05
(0.03) (0.04)
0.05 0.05
(0.06) (0.07)
-0.00 -0.02
(0.01) (0.03)
-0.02 -0.02
(0.02) (0.02)
-0.02* -0.02*
(0.01) (0.01)
0.00 -0.00
(0.02) (0.02)
-0.04 -0.05
(0.03) (0.03)
-0.00 0.00
(0.02) (0.02)
-0.02 -0.01
(0.02) (0.02)
-0.00 -0.01
(0.02) (0.02)
0.06 0.07
(0.04) (0.05)
1003
0.02
Tech Data
Single All tech
0.03 -0.01
(0.04) (0.05)
0.03* 0.03
(0.02) (0.02)
-0.01 0.01
(0.01) (0.02)
-0.03 -0.03
(0.02) (0.03)
-0.01 0.01
(0.02) (0.02)
-0.00 0.00
(0.01) (0.02)
0.05 0.04
(0.04) (0.05)
-0.01 -0.01
(0.01) (0.03)
0.14 0.13
(0.13) (0.14)
-0.01 0.00
(0.02) (0.02)
-0.03 -0.02
(0.02) (0.02)
-0.01 -0.00
(0.04) (0.03)
-0.01 0.00
(0.02) (0.03)
718
0.01
Tech Data plus vehicle
attributes
Single All tech
0.06 0.04
(0.07) (0.07)
0.01 0.02
(0.02) (0.02)
0.02 0.05
(0.03) (0.04)
-0.02 -0.01
(0.03) (0.03)
-0.02 -0.01
(0.03) (0.03)
-0.00 0.03
(0.02) (0.03)
0.12 0.12
(0.08) (0.09)
0.00 0.07
(0.07) (0.09)
0.00 0.00
O (0
-0.02 -0.01
(0.02) (0.02)
-0.02 -0.01
(0.02) (0.03)
-0.01 0.01
(0.03) (0.03)
0.01 0.01
(0.03) (0.03)
660
0.01
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "General Braking" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
41
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Draft - Subject to Revision
Table Al 1: "Tire road noise" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.05 0.03
(0.04) (0.05)
0.01 0.04
(0.02) (0.03)
0.02 0.01
(0.03) (0.03)
0.01 0.03
(0.08) (0.10)
0.04 0.04
(0.02) (0.03)
0.03 0.03
(0.02) (0.02)
-0.01 -0.01
(0.03) (0.03)
-0.02 -0.02
(0.04) (0.04)
-0.02 -0.01
(0.03) (0.03)
-0.08*** -0.08***
(0.02) (0.02)
0.03 0.05
(0.06) (0.07)
-0.05* -0.06
(0.03) (0.05)
-0.00 0.00
(0.04) (0.04)
0.01 -0.00
(0.02) (0.02)
-0.03 -0.02
(0.04) (0.04)
0.08 0.08
(0.05) (0.05)
-0.02 -0.01
(0.03) (0.04)
0.08 0.08
(0.10) (0.10)
0.02 0.02
(0.04) (0.04)
0.01 -0.01
(0.04) (0.04)
1003
0.11
Tech Data
Single All tech
-0.02 0.02
(0.04) (0.05)
-0.03 0.01
(0.03) (0.03)
0.01 0.05
(0.03) (0.03)
-0.06* -0.10**
(0.03) (0.04)
0.02 0.02
(0.04) (0.04)
-0.03 -0.03
(0.03) (0.04)
-0.07** -0.08**
(0.03) (0.04)
0.05 0.03
(0.08) (0.10)
-0.09* -0.10
(0.05) (0.07)
-0.01 0.01
(0.04) (0.04)
0.03 0.04
(0.03) (0.03)
-0.08* -0.08*
(0.04) (0.05)
0.08* 0.07
(0.04) (0.05)
718
0.14
Tech Data plus vehicle
attributes
Single All tech
-0.01 0.04
(0.05) (0.06)
-0.05 -0.03
(0.03) (0.03)
0.07 0.07
(0.05) (0.05)
-0.08* -0.08
(0.05) (0.05)
0.00 0.01
(0.05) (0.05)
-0.02 -0.06
(0.07) (0.07)
-0.05 -0.06
(0.04) (0.05)
0.06 0.18*
(0.08) (0.10)
0.00 0.00
O (0
0.03 0.03
(0.04) (0.04)
0.05 0.07*
(0.03) (0.04)
-0.11** -0.09
(0.04) (0.06)
0.10** 0.11*
(0.05) (0.06)
660
0.15
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Tire Road Noise" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
42
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Draft - Subject to Revision
Table A12: "Wind noise" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.04 -0.02
(0.08) (0.07)
0.02** 0.03
(0.01) (0.02)
0.02 0.02
(0.02) (0.03)
-0.02 -0.02
(0.02) (0.03)
0.00 0.01
(0.02) (0.02)
-0.01 -0.01
(0.01) (0.01)
-0.00 0.01
(0.02) (0.03)
-0.05** -0.06**
(0.02) (0.02)
0.01 0.01
(0.03) (0.03)
-0.01 -0.02
(0.01) (0.01)
0.01 0.01
(0.01) (0.02)
-0.02 -0.03
(0.02) (0.02)
-0.07*** -0.07***
(0.02) (0.02)
-0.01 -0.01
(0.01) (0.01)
0.05* 0.06**
(0.03) (0.03)
-0.05** -0.05**
(0.02) (0.02)
-0.02 0.01
(0.03) (0.03)
-0.10*** -0.11***
(0.03) (0.03)
0.01 0.01
(0.02) (0.02)
0.00 0.01
(0.03) (0.03)
1003
0.09
Tech Data
Single All tech
0.00 -0.01
(0.03) (0.04)
0.02 0.02
(0.02) (0.01)
-0.02 0.00
(0.02) (0.02)
-0.05** -0.06**
(0.02) (0.03)
-0.00 0.01
(0.03) (0.03)
0.00 0.02
(0.03) (0.04)
-0.00 -0.02
(0.01) (0.03)
0.00 -0.05
(0.02) (0.04)
-0.06* -0.11**
(0.04) (0.05)
-0.01 -0.02
(0.01) (0.02)
-0.01 -0.02
(0.02) (0.03)
0.04 0.02
(0.02) (0.03)
-0.04 -0.05
(0.03) (0.03)
718
0.13
Tech Data plus vehicle
attributes
Single All tech
0.02 -0.01
(0.05) (0.05)
0.02 0.03
(0.03) (0.02)
-0.00 -0.00
(0.03) (0.03)
-0.06** -0.09**
(0.03) (0.04)
0.01 0.04
(0.03) (0.04)
-0.01 0.02
(0.05) (0.06)
-0.01 -0.05
(0.02) (0.04)
0.02 -0.07
(0.06) (0.09)
0.00 0.00
O (0
-0.03 -0.02
(0.02) (0.02)
-0.03 -0.05
(0.02) (0.03)
0.05* 0.03
(0.03) (0.04)
-0.03 -0.06
(0.03) (0.04)
660
0.15
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Wind Noise" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
43
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Draft - Subject to Revision
Table A 13: "Interior noise" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.01 -0.01
(0.01) (0.02)
0.00 -0.00
(0.01) (0.01)
0.01 0.00
(0.02) (0.02)
0.00 0.01
(0.01) (0.01)
-0.01** -0.01**
(0.01) (0.01)
0.01 0.00
(0.01) (0.01)
0.00 0.01
(0.02) (0.02)
-0.02* -0.03*
(0.01) (0.02)
-0.00 0.00
(0.01) (0.01)
-0.02** -0.01
(0.01) (0.01)
-0.00 0.00
(0.01) (0.01)
-0.02 -0.02
(0.02) (0.02)
-0.02** -0.02**
(0.01) (0.01)
0.00 -0.00
(0.01) (0.01)
-0.02 -0.02
(0.03) (0.03)
0.03 0.04
(0.03) (0.03)
-0.01 -0.01
(0.02) (0.02)
0.14* 0.15*
(0.08) (0.08)
-0.01 -0.01
(0.01) (0.01)
0.02 0.01
(0.03) (0.03)
1003
0.05
Tech Data
Single All tech
0.02 0.05
(0.04) (0.05)
-0.03* -0.03*
(0.02) (0.02)
-0.00 -0.01
(0.02) (0.02)
0.01 0.02
(0.01) (0.02)
0.01 0.00
(0.02) (0.02)
-0.01 -0.01
(0.01) (0.01)
-0.00 -0.02
(0.01) (0.01)
-0.02 -0.03
(0.01) (0.03)
-0.04 -0.06
(0.03) (0.06)
-0.00 -0.00
(0.01) (0.01)
0.00 -0.01
(0.01) (0.01)
-0.03 -0.04
(0.02) (0.03)
0.01 -0.00
(0.02) (0.02)
718
0.03
Tech Data plus vehicle
attributes
Single All tech
0.04 0.06
(0.06) (0.06)
-0.03 -0.04
(0.03) (0.03)
-0.01 -0.02
(0.02) (0.02)
0.01 0.02
(0.02) (0.02)
0.01 0.00
(0.02) (0.02)
-0.01 -0.04
(0.03) (0.03)
-0.01 -0.05
(0.01) (0.03)
-0.01 -0.05
(0.04) (0.05)
0.00 0.00
O (0
0.01 -0.00
(0.01) (0.01)
-0.00 -0.01
(0.01) (0.02)
-0.04 -0.06*
(0.03) (0.03)
0.01 -0.01
(0.02) (0.02)
660
0.02
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Interior Noise" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
44
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Draft - Subject to Revision
Table A14: "Powertrain noise" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.02 -0.00
(0.06) (0.06)
.034*** .Q.31***
(0.10) (0.10)
-0 22*** -0 22***
(0.08) (0.08)
0.01 0.04
(0.11) (0.12)
0.01 0.01
(0.03) (0.03)
0.00 0.02
(0.03) (0.03)
-0.03 -0.04
(0.04) (0.04)
0.04 0.05
(0.06) (0.07)
-0.04 -0.03
(0.05) (0.05)
0.07 0.04
(0.06) (0.06)
0.19 0.24*
(0.12) (0.12)
-0.05 -0.15
(0.09) (0.09)
-0.01 -0.01
(0.05) (0.05)
-0.03 -0.01
(0.03) (0.03)
0.16*** 0.16***
(0.06) (0.06)
-0.04 -0.04
(0.05) (0.05)
0.09 0.10
(0.15) (0.15)
-0.19** -0.22***
(0.07) (0.08)
-0.01 0.00
(0.04) (0.04)
-0.06 -0.07
(0.06) (0.05)
1003
0.14
Tech Data
Single All tech
-0.02 -0.05
(0.08) (0.10)
-0.02 -0.01
(0.04) (0.04)
0.02 0.04
(0.05) (0.04)
-0.02 -0.03
(0.04) (0.05)
0.02 0.03
(0.06) (0.06)
-0.04 -0.03
(0.06) (0.07)
0.02 0.06
(0.06) (0.07)
0.19 0.21
(0.15) (0.16)
-0.22*** -0.17**
(0.06) (0.08)
-0.05 -0.03
(0.06) (0.06)
-0.04 -0.00
(0.04) (0.05)
0.06 0.11
(0.07) (0.08)
0.06 0.05
(0.05) (0.06)
718
0.16
Tech Data plus vehicle
attributes
Single All tech
0.04 -0.01
(0.12) (0.13)
-0.07* -0.04
(0.04) (0.04)
-0.05 -0.02
(0.08) (0.07)
-0.10* -0.09*
(0.05) (0.05)
0.03 0.05
(0.06) (0.07)
-0.09 -0.07
(0.11) (0.11)
0.00 0.02
(0.11) (0.12)
1.10*** 1.06***
(0.10) (0.14)
0.00 0.00
O (0
-0.01 0.01
(0.06) (0.06)
-0.03 0.01
(0.05) (0.05)
0.05 0.07
(0.08) (0.08)
0.07 0.08
(0.05) (0.06)
660
0.19
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Powertrain Noise" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
45
-------
Draft - Subject to Revision
Table A15: "General noise" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.09 -0.09
(0.09) (0.09)
0.01 0.02
(0.02) (0.02)
0.01 0.02
(0.03) (0.03)
0.04 0.04
(0.09) (0.08)
-0.02 -0.02
(0.02) (0.02)
-0.02 -0.01
(0.02) (0.02)
0.00 0.02
(0.03) (0.03)
-0.04 -0.04
(0.04) (0.04)
0.00 0.00
(0.03) (0.03)
0.03 0.01
(0.04) (0.03)
-0.02 -0.03
(0.02) (0.03)
0.03 0.02
(0.06) (0.06)
0.02 0.02
(0.04) (0.04)
-0.04*** -0.04**
(0.02) (0.02)
0.05 0.04
(0.05) (0.05)
0.01 0.01
(0.04) (0.04)
-0.06** -0.06
(0.02) (0.04)
-0.09 -0.09
(0.08) (0.08)
-0.01 -0.01
(0.02) (0.03)
-0.02 -0.01
(0.04) (0.04)
1003
0.14
Tech Data
Single All tech
0.03 0.05
(0.05) (0.06)
-0.02 -0.02
(0.03) (0.03)
0.01 0.03
(0.02) (0.03)
-0.05* -0.06**
(0.03) (0.03)
-0.01 0.00
(0.02) (0.02)
-0.02 -0.02
(0.04) (0.04)
0.01 -0.03
(0.04) (0.05)
-0.02 -0.07
(0.02) (0.04)
-0.05 -0.11**
(0.03) (0.06)
0.00 0.01
(0.05) (0.05)
-0.02 -0.02
(0.03) (0.03)
-0.03 -0.05
(0.06) (0.06)
0.01 -0.02
(0.04) (0.04)
718
0.17
Tech Data plus vehicle
attributes
Single All tech
0.04 0.05
(0.07) (0.08)
-0.04 -0.02
(0.04) (0.04)
-0.03 -0.05
(0.04) (0.04)
-0.07** -0.07**
(0.03) (0.03)
-0.01 0.01
(0.03) (0.03)
0.00 -0.04
(0.05) (0.06)
-0.05* -0.10**
(0.03) (0.05)
-0.01 -0.11
(0.07) (0.09)
0.00 0.00
O (0
0.01 0.01
(0.04) (0.05)
-0.00 -0.01
(0.03) (0.04)
-0.02 -0.04
(0.06) (0.06)
0.03 0.00
(0.03) (0.04)
660
0.20
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "General Noise" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
46
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Draft - Subject to Revision
Table A16: "Chassis vibration" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.00 -0.00
(0.01) (0.01)
-0.00 0.00
(0.01) (0.01)
0.01 -0.00
(0.00) (0.00)
-0.00 -0.00
(0.01) (0.01)
0.02 0.02*
(0.01) (0.01)
0.01 0.00
(0.01) (0.01)
-0.02* -0.01
(0.01) (0.01)
-0.04 -0.03
(0.02) (0.02)
0.00 0.00
(0.00) (0.01)
-0.01 -0.01
(0.01) (0.01)
-0.01 -0.01
(0.01) (0.01)
0.01 0.02
(0.01) (0.01)
-0.00 -0.01
(0.01) (0.01)
0.00 0.00
(0.01) (0.01)
0.01 0.01
(0.01) (0.01)
0.01 0.01
(0.01) (0.02)
-0.01 -0.02
(0.02) (0.02)
0.01* 0.01
(0.01) (0.01)
-0.01* -0.01*
(0.01) (0.01)
-0.01 -0.01
(0.01) (0.01)
1003
0.02
Tech Data
Single All tech
-0.00 -0.00
(0.00) (0.01)
0.01 0.01
(0.01) (0.01)
-0.00 -0.01
(0.00) (0.00)
0.00 0.00
(0.01) (0.01)
-0.01 -0.01
(0.01) (0.01)
0.00 0.01
(0.01) (0.01)
-0.01 -0.00
(0.01) (0.01)
-0.00 0.00
(0.01) (0.01)
0.01 0.01
(0.01) (0.01)
-0.00 -0.00
(0.00) (0.00)
0.00 0.01
(0.00) (0.01)
0.01 0.01
(0.01) (0.02)
0.01 0.02
(0.01) (0.02)
718
-0.01
Tech Data plus vehicle
attributes
Single All tech
-0.01 -0.02
(0.01) (0.02)
0.01 0.01
(0.01) (0.01)
-0.01 -0.01
(0.01) (0.01)
-0.00 -0.00
(0.01) (0.01)
-0.00 -0.00
(0.01) (0.01)
0.02 0.01
(0.01) (0.01)
-0.00 0.01
(0.01) (0.01)
-0.04 -0.02
(0.04) (0.04)
0.00 0.00
(.) (.)
-0.01 -0.00
(0.01) (0.01)
0.00 0.01
(0.00) (0.01)
0.01 0.02
(0.01) (0.02)
0.02 0.02
(0.02) (0.02)
660
-0.02
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Chassis Vibration" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on
all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
47
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Draft - Subject to Revision
Table A17: "Powertrain vibration" negative review linear probability model regressions on efficiency
technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.01 -0.01
(0.01) (0.01)
-0.00 0.00
(0.01) (0.01)
-0.01 -0.02
(0.02) (0.02)
-0.01 -0.01
(0.01) (0.01)
0.00 0.00
(0.01) (0.01)
0.01 0.01
(0.01) (0.01)
-0.01 -0.01
(0.01) (0.01)
0.01 0.02
(0.02) (0.03)
0.01 0.01
(0.02) (0.02)
-0.00 -0.00
(0.00) (0.00)
-0.00 0.01
(0.01) (0.01)
-0.01 -0.00
(0.01) (0.01)
0.01 0.01
(0.02) (0.02)
0.00 0.00
(0.01) (0.01)
0.01 0.01
(0.01) (0.01)
0.01 0.01
(0.02) (0.02)
-0.02 -0.02
(0.02) (0.03)
-0.01 -0.01
(0.01) (0.01)
0.00 0.01
(0.01) (0.02)
-0.02* -0.02*
(0.01) (0.01)
1003
0.01
Tech Data
Single All tech
-0.01 -0.01
(0.01) (0.01)
-0.01 -0.01
(0.02) (0.02)
0.01 0.01
(0.01) (0.01)
0.00 -0.00
(0.01) (0.01)
0.02 0.02
(0.02) (0.02)
0.01 0.01
(0.02) (0.02)
-0.00 0.00
(0.00) (0.01)
-0.00 -0.00
(0.01) (0.01)
-0.01 -0.00
(0.01) (0.01)
-0.00 -0.01
(0.02) (0.02)
0.01 0.00
(0.01) (0.01)
0.01 0.01
(0.02) (0.02)
-0.02* -0.02
(0.01) (0.01)
718
0.02
Tech Data plus vehicle
attributes
Single All tech
-0.02* -0.03
(0.01) (0.02)
-0.01 -0.02
(0.02) (0.02)
0.01 0.00
(0.03) (0.03)
-0.00 -0.00
(0.01) (0.01)
0.02 0.02
(0.02) (0.02)
-0.02 -0.03
(0.03) (0.03)
-0.00 0.01
(0.01) (0.02)
-0.00 -0.02
(0.04) (0.04)
0.00 0.00
C) (0
-0.01 -0.01
(0.03) (0.03)
0.01 0.02
(0.01) (0.01)
-0.00 0.01
(0.02) (0.02)
-0.01 -0.01
(0.01) (0.01)
660
0.02
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Powertrain Vibration" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions
on all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported
in parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
48
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Draft - Subject to Revision
Table A18: "General vibration" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.01 -0.01
(0.02) (0.02)
-0.00 -0.01
(0.01) (0.02)
-0.01 -0.01
(0.01) (0.01)
0.06 0.08
(0.06) (0.06)
-0.01 -0.02
(0.01) (0.01)
-0.00 -0.00
(0.01) (0.01)
0.02 0.02
(0.02) (0.02)
0.02 0.01
(0.02) (0.02)
-0.01* -0.01
(0.01) (0.01)
-0.01 -0.01
(0.01) (0.01)
0.00 0.02
(0.01) (0.01)
-0.01 -0.03
(0.01) (0.02)
0.03 0.03
(0.03) (0.03)
-0.00 0.00
(0.01) (0.01)
0.02 0.02
(0.02) (0.02)
0.03 0.03
(0.03) (0.03)
-0.01 -0.02
(0.02) (0.03)
0.01 0.01
(0.01) (0.02)
0.00 0.01
(0.02) (0.02)
-0.04** -0.04***
(0.01) (0.02)
1003
0.06
Tech Data
Single All tech
0.01 0.00
(0.01) (0.02)
0.01 0.01
(0.01) (0.01)
0.02 0.02
(0.01) (0.02)
0.01 0.01
(0.01) (0.01)
-0.01 -0.02
(0.01) (0.01)
-0.01 -0.02
(0.01) (0.02)
-0.01 0.00
(0.01) (0.02)
0.00 0.02
(0.01) (0.02)
0.00 0.01
(0.02) (0.02)
0.01 0.01
(0.02) (0.02)
-0.00 0.00
(0.02) (0.02)
0.03 0.04
(0.02) (0.03)
0.01 0.01
(0.03) (0.03)
718
0.10
Tech Data plus vehicle
attributes
Single All tech
-0.00 -0.00
(0.02) (0.02)
0.01 0.02
(0.01) (0.01)
0.02 0.02
(0.02) (0.03)
0.00 -0.00
(0.01) (0.01)
-0.01 -0.02
(0.01) (0.02)
-0.03 -0.03
(0.03) (0.04)
-0.03 -0.01
(0.02) (0.03)
0.06 0.10*
(0.04) (0.06)
0.00 0.00
O (0
0.01 0.02
(0.02) (0.02)
-0.00 0.01
(0.02) (0.02)
0.04 0.04
(0.03) (0.03)
0.02 0.04
(0.04) (0.04)
660
0.11
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "General Vibration" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on
all technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
49
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Draft - Subject to Revision
Table A19: "Ride comfort" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
-0.02 -0.04
(0.13) (0.14)
-0.03 -0.05
(0.05) (0.06)
-0.05 0.03
(0.05) (0.07)
0.11 0.08
(0.11) (0.10)
-0.00 -0.02
(0.03) (0.03)
-0.04 -0.03
(0.03) (0.03)
0.07 0.05
(0.05) (0.05)
0.06 0.04
(0.08) (0.08)
.0.14*** -0.12**
(0.05) (0.05)
-0.01 -0.02
(0.05) (0.05)
-0.09** -0.12**
(0.04) (0.05)
0.08 0.10
(0.09) (0.08)
0.00 0.02
(0.07) (0.07)
0.01 0.02
(0.03) (0.03)
-0.02 -0.01
(0.05) (0.05)
0.06 0.06
(0.06) (0.06)
-0.06 -0.09*
(0.05) (0.05)
-0.10 -0.11
(0.10) (0.10)
0.07 0.07
(0.05) (0.05)
-0.02 -0.03
(0.06) (0.07)
1003
0.12
Tech Data
Single All tech
-0.18*** -0.15**
(0.05) (0.06)
-0.09** -0.05
(0.04) (0.05)
-0.08** -0.08*
(0.04) (0.05)
-0.06 -0.04
(0.04) (0.05)
0.08 0.07
(0.06) (0.07)
-0.19*** -0.10*
(0.05) (0.06)
-0.01 -0.01
(0.05) (0.07)
-0.08 -0.08
(0.10) (0.10)
-0.16*** -0.12
(0.06) (0.07)
-0.07 -0.02
(0.07) (0.07)
-0.02 0.00
(0.04) (0.04)
-0.08 -0.04
(0.05) (0.06)
0.20*** 0.15**
(0.06) (0.07)
718
0.16
Tech Data plus vehicle
attributes
Single All tech
-0.13* -0.14*
(0.07) (0.08)
-0.07 -0.05
(0.05) (0.05)
0.02 0.00
(0.07) (0.08)
-0.03 -0.02
(0.05) (0.06)
0.05 0.08
(0.08) (0.08)
0.07 0.05
(0.10) (0.10)
0.00 0.05
(0.07) (0.09)
0.00 0.12
(0.11) (0.16)
0.00 0.00
O (0
0.05 0.05
(0.07) (0.07)
-0.01 0.01
(0.04) (0.05)
-0.10* -0.05
(0.06) (0.07)
0.18** 0.17**
(0.07) (0.08)
660
0.16
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Ride Comfort" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
50
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Draft - Subject to Revision
Table A20: "Fuel eco
nomy" negath
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
?Q review linear
Any coded mention of
tech in review
Single All tech
0.05 0.06
(0.05) (0.06)
-0.09 -0.05
(0.06) (0.07)
-0.25** -0.18*
(0.11) (0.09)
-0.17*** -0.17***
(0.04) (0.05)
0.01 0.02
(0.03) (0.03)
0.02 0.04
(0.03) (0.03)
-0.09*** -0.05
(0.03) (0.03)
-0.17*** -0.14**
(0.06) (0.06)
-0.13*** -0.15***
(0.04) (0.05)
-0.02 -0.02
(0.05) (0.05)
-0.06 -0.06
(0.07) (0.06)
-0.05 0.01
(0.07) (0.07)
-0.02 -0.01
(0.06) (0.06)
-0.04 -0.05*
(0.02) (0.03)
-0.04 -0.04
(0.06) (0.06)
-0.03 -0.06
(0.03) (0.04)
-0.13** -0.11*
(0.07) (0.06)
-0.15* -0.14
(0.09) (0.10)
-0.07** -0.07**
(0.03) (0.03)
0.01 0.06
(0.05) (0.05)
1003
0.13
Drobability model regressions on efficiency technology
Tech Data
Single All tech
-0.18** -0.16*
(0.07) (0.08)
-0.12** -0.11**
(0.05) (0.05)
-0.00 0.03
(0.04) (0.05)
-0.09* -0.10*
(0.05) (0.06)
-0.09 -0.10
(0.06) (0.06)
-0.10* -0.09
(0.06) (0.06)
0.01 -0.02
(0.07) (0.08)
-0.09 -0.12
(0.09) (0.11)
-0.16*** -0.17**
(0.06) (0.08)
-0.12* -0.12*
(0.06) (0.07)
0.00 -0.00
(0.04) (0.04)
-0.04 -0.01
(0.07) (0.08)
0.01 -0.08
(0.05) (0.06)
718
0.10
Tech Data plus vehicle
attributes
Single All tech
-0.15 -0.24**
(0.11) (0.12)
-0.10* -0.13**
(0.06) (0.06)
0.01 -0.06
(0.08) (0.09)
-0.11* -0.05
(0.06) (0.07)
-0.15** -0.15**
(0.07) (0.08)
-0 21** -0 33***
(0.09) (0.11)
0.20 0.17
(0.12) (0.13)
-0.25* -0.53***
(0.14) (0.20)
0.00 0.00
O (0
-0.11 -0.13*
(0.07) (0.07)
-0.04 -0.01
(0.04) (0.05)
-0.04 0.01
(0.08) (0.09)
-0.01 -0.03
(0.06) (0.07)
660
0.14
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Fuel Economy" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
51
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Draft - Subject to Revision
Table A21: "Range" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.01 0.00
(0.01) (0.01)
0.00 0.00
(0.00) (0.00)
0.00 0.00
(0.01) (0.01)
0.05 0.02
(0.07) (0.07)
0.00 0.00
(0.01) (0.01)
-0.01** -0.00
(0.01) (0.00)
0.00 0.00
(0.00) (0.00)
0.01* 0.01
(0.01) (0.01)
-0.01 -0.01
(0.01) (0.01)
-0.02* -0.01
(0.01) (0.01)
0.28*** 0.27**
(0.11) (0.11)
0.10 0.02
(0.08) (0.08)
0.01 0.02
(0.02) (0.02)
-0.01 -0.00
(0.00) (0.00)
-0.02* -0.02**
(0.01) (0.01)
-0.00 0.00
(0.00) (0.00)
-0.00 -0.00
(0.01) (0.02)
-0.01 -0.00
(0.01) (0.01)
-0.01* -0.01
(0.00) (0.01)
0.02 0.00
(0.03) (0.02)
1003
0.17
Tech Data
Single All tech
0.01 -0.03
(0.03) (0.03)
0.00 0.00
(0.00) (0.01)
-0.01 0.01
(0.01) (0.01)
-0.01 0.01
(0.01) (0.01)
0.00 0.00
(0.01) (0.01)
-0.00 -0.01
(0.01) (0.01)
-0.02 -0.00
(0.01) (0.01)
0.26** 0.28**
(0.12) (0.12)
-0.02 0.04
(0.01) (0.03)
0.00 0.01
(0.00) (0.01)
-0.01 0.01
(0.01) (0.01)
-0.02* -0.01
(0.01) (0.01)
-0.00 0.01
(0.00) (0.01)
718
0.14
Tech Data plus vehicle
attributes
Single All tech
-0.01 0.00
(0.01) (0.01)
0.00 -0.00
(0.00) (0.00)
0.02 0.02
(0.02) (0.02)
0.01 0.02
(0.01) (0.01)
0.00 -0.01
(0.00) (0.01)
-0.01 -0.01
(0.02) (0.02)
-0.00 0.00
(0.00) (0.01)
-0.02 0.02
(0.02) (0.03)
0.00 0.00
O (0
-0.00 -0.00
(0.00) (0.01)
0.01 0.01
(0.01) (0.01)
-0.01 -0.01
(0.01) (0.01)
0.00 0.01
(0.01) (0.01)
660
0.01
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Range" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
52
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Draft - Subject to Revision
Table A22: "Charging" negative review linear probability model regressions on efficiency technology
Active Air Dam
Active Grille
Shutters
Active Ride Height
Low Resistance
Tires
Electronic Power
Steering
Turbocharged
GDI
Cylinder
Deactivation
Diesel
Hybrid
Plug-In Hybrid
Electric
Full Electric
Stop-Start
High Speed
Automatic
CVT
DCT
Elec Assist / Low
Drag Brakes
Lighting-LED
Mass Reduction
Passive
Aerodynamics
Observations
Adj-R2
Any coded mention of
tech in review
Single All tech
0.00 0.00
(0.00) (0.00)
0.00 0.00
(0.00) (0.00)
0.01 0.00
(0.00) (0.01)
0.00 -0.01
(0.00) (0.02)
-0.00 -0.00
(0.00) (0.00)
-0.00 -0.00
(0.00) (0.00)
-0.00 0.00
(0.00) (0.00)
-0.00 -0.00
(0.00) (0.00)
0.01 0.01
(0.00) (0.00)
0.00 0.00
(0.00) (0.00)
0.09 0.10
(0.06) (0.08)
0.03 0.00
(0.05) (0.07)
-0.00 0.00
(0.00) (0.00)
-0.00 -0.00
(0.00) (0.00)
0.00 0.00
(0.00) (0.00)
-0.00 -0.00
(0.00) (0.00)
-0.01 -0.00
(0.01) (0.01)
0.00 0.01
(0.00) (0.00)
0.01 0.02
(0.02) (0.02)
0.00 -0.01
(0.00) (0.01)
1003
0.07
Tech Data
Single All tech
0.08* 0.05*
(0.04) (0.03)
0.01 0.01
(0.00) (0.00)
-0.01 0.00
(0.01) (0.00)
-0.02* -0.00
(0.01) (0.00)
-0.01 -0.00
(0.01) (0.00)
0.01 0.00
(0.01) (0.01)
0.00 0.00
(0.00) (0.00)
0.07 0.06
(0.05) (0.05)
0.10 0.08
(0.12) (0.11)
0.00 0.01
(0.00) (0.00)
-0.01* 0.00
(0.01) (0.00)
0.00 -0.00
(0.00) (0.00)
-0.01 0.00
(0.01) (0.00)
718
0.10
Tech Data plus vehicle
attributes
Single All tech
Results in the "Single" columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative
review of "Charging" on the single technology given by the row plus fixed effects. The "All tech" columns represent single regressions on all
technology variables. All regressions include make, class, and review website fixed effects. Eicker-Huber-White standard errors are reported in
parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels.
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