February 2009 Bibliometric Analysis for the U.S. Environmental Protection Agency/Office of Research and Development's Endocrine Disrupting Chemicals (EDCs) Research Program This is a bibliometric analysis of the papers prepared by intramural and extramural researchers of the U.S. Environmental Protection Agency's (EPA) Endocrine Disrupting Chemicals (EDCs) Research Program. For this analysis, 698 (652 journal articles and 46 non-journal publications) were reviewed, and they were published from 1998 to 2008. The journal articles were cited 12,895 times and the non-journal publications were cited 180 times in the journals covered by Thomson's Web of Science1 and Scopus2. Of the 652 journal articles, 598 (91.7%) have been cited at least once in a journal. Of the 46 non-journal publications, 20 (43.5%) have been cited at least once in a journal. Searches of Thomson Scientific's Web of Science and Elsevier's Scopus were conducted to obtain times cited data for the EDCs journal publications. The analysis was completed using Thomson's Essential Science Indicators (ESI) and Journal Citation Reports (JCR) as benchmarks. ESI provides access to a unique and comprehensive compilation of essential science performance statistics and science trends data derived from Thomson's databases. For this analysis, the ESI highly cited papers thresholds as well as the hot papers thresholds were used to assess the influence and impact of the EDCs papers. JCR is a recognized authority for evaluating journals. It presents quantifiable statistical data that provide a systematic, objective way to evaluate the world's leading journals and their impact and influence in the global research community. The two key measures used in this analysis to assess the journals in which the EPA EDCs papers are published are the Impact Factor and Immediacy Index. The Impact Factor is a measure of the frequency with which the "average article" in a journal has been cited in a particular year. The Impact Factor helps evaluate a journal's relative importance, especially when compared to other journals in the same field. The Immediacy Index is a measure of how quickly the "average article" in a journal is cited. This index indicates how often articles published in a journal are cited within the same year and it is useful in comparing how quickly journals are cited. The report includes a summary of the results of the bibliometric analysis, an analysis of the 652 EDCs journal papers analyzed by ESI field (e.g., Environment/Ecology, Pharmacology & Toxicology, Plant & Animal Science), an analysis of the journals in which the EDCs papers were published, a table of the highly cited researchers in the EDCs Research Program, an analysis of the non-journal publications, and any patents that have resulted from the program. Thomson Scientific's Web of Science provides access to current and retrospective multidisciplinary information from approximately 8,830 of the most prestigious, high impact research journals in the world. Web of Science also provides cited reference searching. 2 Scopus is a large abstract and citation database of research literature and quality Web sources designed to support the literature research process. Scopus offers access to 15,000 titles from 4,000 different publishers, more than 12,850 academic journals (including coverage of 535 Open Access journals, 750 conference proceedings, and 600 trade publications), 27 million abstracts, 245 million references, 200 million scientific Web pages, and 13 million patent records. ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 SUMMARY OF RESULTS l. More than one-quarter of the EDCs publications are highly cited papers. 181 (27.8%) of the EDCs papers qualify as highly cited when using the ES/ criteria for the top 10% of highly cited publications. This is 2.8 times the 10% of papers expected to be highly cited. 27 (4.1%) of the EDCs papers qualify as highly cited when using the ES/ criteria for the top 1 %, which is 4.1 times the number expected. 3 (0.5%) of these papers qualify as very highly cited when using the criteria for the top 0.1%, which is 5 times the number anticipated. 2 (0.3%) papers actually meet the 0.01 % threshold for the most highly cited papers, which is 30 times the expected number for this program. 2. The EDCs papers are more highly cited than the average paper. Using the ESI average citation rates for papers published by field as the benchmark, in 12 of the 16 fields in which the 562 EDCs journal papers were published, the ratio of actual to expected cites is greater than 1, indicating that the EDCs papers are more highly cited than the average papers in those fields. For all 16 fields combined, the ratio of total number of cites to the total number of expected cites (12,895 to 6,667) is 1.9, indicating that the EDCs papers are more highly cited than the average paper. 3. Nearly one-half of the EDCs papers are published in high impact journals ranked by Impact Factor. 272 of the 652 papers were published in the top 10% of journals ranked by JCF? Impact Factor, representing 41.7% of the EDCs journal papers. This number is 4.2 times higher than the expected 65 papers. 184 of the 652 papers appear in the top 10% of journals ranked by JCf? Immediacy Index, representing 28.2% of the EDCs journal papers. This number is 2.8 times higher than the expected 65 papers. 4. Six of the EDCs journal papers qualify as hot papers. Using the hot paper thresholds established by ESI as a benchmark, 6 hot papers, representing 0.9% of the EDCs papers, were identified in the analysis. Hot papers are papers that were highly cited shortly after they were published. The number of EDCs hot papers identified is 9 times higher than the expected 0.6 hot papers. 5. The authors of the EDCs papers cite themselves much less than the average author. 544 of the 12,895 cites are author self-cites. This 4.2% author self-citation rate is well below the accepted range of 10-30% author self-citation rate. 6. Twenty-one of the authors of the EDCs papers are included in ISIHighlyCited.com, which is a database of the world's most influential researchers who have made key contributions to science and technology during the period from 1981 to 1999. 7. No patents were issued and no patent applications were filed by investigators from 1997 to 2007 for research that was conducted under EPA's EDCs research program. 8. The 46 nonjournal publications were cited 180 times in journals. 20 (43.5%) were cited at least once in a journal and the authors cited themselves 9 times (5.0% self-citation rate), which is much less than the literature-reported 10-30% range for author self-citation. 2(4.4%) of the nonjournal publications were highly cited when using the ESI criteria for the top 10% of highly cited publications. ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 Highly Cited EDCs Publications All of the journals covered by ESI are assigned a field, and to compensate for varying citation rates across scientific fields, different thresholds are applied to each field. Thresholds are set to select highly cited papers to be listed in ESI. Different thresholds are set for both field and year of publication. Setting different thresholds for each year allows comparable representation for older and younger papers for each field. The 652 EDCs research papers reviewed for this analysis were published in journals that were assigned to 16 of the 22 ESI fields. The distribution of the papers among these 16 fields and the number of citations by field are presented in Table 1. Tablet. EDCs Papers by ESI Fields ESI Field Agricultural Sciences Biology & Biochemistry Chemistry Clinical Medicine Computer Science Engineering Environment/Ecology Geosciences Mathematics Microbiology Molecular Biology & Genetics Multidisciplinary Neuroscience & Behavior Pharmacology & Toxicology Plant & Animal Science Social Sciences, general No. of Citations 26 1,390 398 1,626 3 29 3,362 7 0 1 64 1,100 274 3,582 1,007 26 Total = 12,895 No. of EPA Papers 3 79 36 74 2 5 195 1 1 1 7 10 26 138 72 2 Total = 652 Average Cites/Paper 8.7 17.6 11.0 22.0 1.5 5.8 17.2 7.0 0 1.0 9.1 110.0 10.5 26.0 14.0 13.0 19.8 There are 181 (27.8% of the papers analyzed) highly cited EPA EDCs papers in 12 of the 16 fields— Agricultural Sciences, Biology & Biochemistry, Chemistry, Clinical Medicine, Computer Science, Engineering, Environment/Ecology, Multidisciplinary, Neuroscience & Behavior, Pharmacology & Toxicology, Plant & Animal Science, and Social Sciences—when using the ESI criteria for the top 10% of papers. Table 2 shows the number of EPA papers in those 12 fields that meet the top 10% ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 threshold in ESI Twenty-seven (4.1%) of the papers analyzed qualify as highly cited when using the ESI criteria for the top 1% of papers. These papers cover 6 fields—Biology & Biochemistry, Clinical Medicine, Engineering, Environment/Ecology, Multidisciplinary, and Pharmacology & Toxicology. Table 3 shows the 27 papers by field that meet the top 1% threshold in ESI The citations for these 27 papers are provided in Tables 4 through 9. There were 3 (0.5%) very highly cited EDCs papers in the fields of Environment/Ecology and Multidisciplinary (see Table 10). These papers, which met the top 0.1% threshold in ESI, are listed in Table 11. Two (0.3%) of the EDCs papers met the top 0.01% threshold in ESI (see Table 12), which is 30 times the expected number of papers that should meet this threshold for this size program. These papers are listed in Table 13. Table 2. Number of Highly Cited EDCs Papers by Field (top 10%) ESI Field Agricultural Sciences Biology & Biochemistry Chemistry Clinical Medicine Computer Science Engineering Environment/Ecology Multidisciplinary Neuroscience & Behavior Pharmacology & Toxicology Plant & Animal Science Social Sciences, general No. of Citations 21 506 183 940 3 24 2,077 1,080 11 2,539 779 17 Total = 8,180 No. of Papers 1 16 5 21 1 2 56 7 1 44 26 1 Total = 181 Average Cites/Paper 21.0 31.6 36.6 44.8 3.0 12.0 37.1 154.3 11.0 57.7 30.0 17.0 45.2 % of Papers in Field 33.3% 20.2% 13.9% 28.4% 50.0% 40.0% 28.7% 70.0% 3.8% 31.9% 36.1% 50.0% 27.8% Table 3. Number of Highly Cited EDCs Papers by Field (top 1%) ESI Field Biology & Biochemistry Clinical Medicine Engineering Environment/Ecology Multidisciplinary No. of Citations 47 213 22 632 1,027 No. of Papers 1 4 1 9 6 Average Cites/Paper 47.0 53.2 22.0 70.2 171.2 % of EPA Papers in Field 1.3% 5.4% 20.0% 4.6% 60.0% ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 ESI Field Pharmacology & Toxicology No. of Citations 841 Total = 2,782 No. of Papers 6 Total = 27 Average Cites/Paper 140.2 103.0 % of EPA Papers in Field 4.4% 4.1% Table 4. Highly Cited EDCs Papers in the Field of Biology & Biochemistry (top 1%) No. of Cites 47 First Author Anway MD Paper Epigenetic transgenerational actions of endocrine disrupters. Endocrinology 2006; 147(6): S43-S49. Table 5. Highly Cited EDCs Papers in the Field of Clinical Medicine (top 1%) No. of Cites 151 48 6 8 First Author Gray LE Gray LE Euling SY Rider CV Paper Effects of environmental antiandrogens on reproductive development in experimental animals. Human Reproduction Update 2001;7(3):248- 264. Adverse effects of environmental antiandrogens and androgens on reproductive development in mammals. InternationalJournal of Andrology 2006;29(1):96-104. Examination of US puberty-timing data from 1940 to 1994 for secular trends: Panel findings. Pediatrics 2008;121:S172-S191. A mixture of seven antiandrogens induces reproductive malformations in rats. International Journal of Andrology 2008;3 1(2):249-262. Table 6. Highly Cited EDCs Papers in the Field of Engineering (top 1%) No. of Cites 22 First Author De Jesus MA Paper Nanofabrication of densely packed metal -polymer arrays for surface- enhanced Raman spectrometry. Applied Spectroscopy 2005;59(12):1501-1508. ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 Table 7. Highly Cited EDCs Papers in the Field of Environment/Ecology (top 1%) No. of Cites 187 130 48 186 18 18 26 5 14 First Author Crisp TM Ankley GT Mills LJ Swan SH LeBlanc GA Villeneuve DL Mergler D Kostich MS Lorber M Paper Environmental endocrine disruption: an effects assessment and analysis. Environmental Health Perspectives 1998;106(Suppl 1):11- 56. Description and evaluation of a short-term reproduction test with the fathead minnow (Pimephales promelas). Environmental Toxicology and Chemistry 2001 ;20(6): 1276-1290. Review of evidence: are endocrine-disrupting chemicals in the aquatic environment impacting fish populations? Science of the Total Environment 2005;343(l-3): 1-34. Decrease in anogenital distance among male infants with prenatal phthalate exposure. Environmental Health Perspectives 2005;113(8):1056-1061. Crustacean endocrine toxicology: a review. Ecotoxicology 2007;16(1):61-81. A graphical systems model to facilitate hypothesis-driven ecotoxicogenomics research on the teleost brain-pituitary-gonadal axis. Environmental Science & Technology 2007;41(1):321-330. Methylmercury exposure and health effects in humans: a worldwide concern. Ambio 2007;36(1):3-11. Risks to aquatic organisms posed by human pharmaceutical use. Science of the Total Environment 2008;389(2-3):329-339. Exposure of Americans to polybrominated diphenyl ethers. Journal of Exposure Science and Environmental Epidemiology 2008;18(1):2-19. Table 8. Highly Cited EDCs Papers in the Field of Multidisciplinary (top 1%) No. of Cites First Author Paper 160 Hawkins MB Identification of a third distinct estrogen receptor and reclassification of estrogen receptors in teleosts. Proceedings of the National Academy of Sciences of the United States of America 2000;97(20): 10751-10756. 248 ZhuY Cloning, expression, and characterization of a membrane progestin receptor and evidence it is an intermediary in meiotic maturation of fish oocytes. Proceedings of the National Academy of Sciences of the United States of America 2003; 100(5):2231-2236. ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 No. of Cites 252 69 259 39 First Author ZhuY Timms BG Anway MD KiddKA Paper Identification, classification, and partial characterization of genes in humans and other vertebrates homologous to a fish membrane progestin receptor. Proceedings of the National Academy of Sciences of the United States of America 2003;100(5):2237-2242. Estrogenic chemicals in plastic and oral contraceptives disrupt development of the fetal mouse prostate and urethra. Proceedings of the National Academy of Sciences of the United States of America 2005;102(19):7014-7019. Epigenetic transgenerational actions of endocrine disrupters and mate fertility. Science 2005;308(5727): 1466-1469. Collapse of a fish population after exposure to a synthetic estrogen. Proceedings of the National Academy of Sciences of the United States o/^iwenca2007;104(21):8897-8901. Table 9. Highly Cited EDCs Papers in the Field of Pharmacology & Toxicology (top 1%) No. of Cites 195 209 217 126 89 5 First Author Parks LG Laws SC Gray LE Zhou T Wilson VS Richardson VM Paper The plasticizer diethylhexyl phthalate induces malformations by decreasing fetal testosterone synthesis during sexual differentiation in the male rat. Toxicological Sciences 2000;58(2):339-349. Estrogenic activity of octylphenol, nonylphenol, bisphenol A and methoxychlor in rats. Toxicological Sciences 2000;54(1): 154-167. Perinatal exposure to the phthalates DEHP, BBP, and DINP, but not DEP, BMP, or DOTP, alters sexual differentiation of the male rat. Toxicological Sciences 2000;58(2):350-365. Developmental exposure to brominated diphenyl ethers results in thyroid hormone disruption. Toxicological Sciences 2002;66(1): 105- 116. Phthalate ester-induced gubernacular lesions are associated with reduced ins!3 gene expression in the fetal rat testis. Toxicology Letters 2004;146(3):207-215. Possible mechanisms of thyroid hormone disruption in mice by BDE 47, a major polybrominated diphenyl ether congener. Toxicology and Applied Pharmacology 2008 ;226(3) : 244-25 0 . ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 Table 10. Number of Very Highly Cited EDCs Papers by Field (top 0.1%) ESI Field Environment/Ecology Multidisciplinary No. of Citations 200 259 Total = 459 No. of Papers 2 1 Total = 3 Average Cites/Paper 100.0 259.0 153.0 % of EPA Papers in Field 1.0% 10.0% 0.5% Table 11. Very Highly Cited EDCs Papers (top 0.1%) ESI Field Environment/ Ecology Multidisciplinary No. of Cites 186 14 259 First Author Swan SH Lorber M Anway MD Paper Decrease in anogenital distance among male infants with prenatal phthalate exposure. Environmental Health Perspectives 2005;113(8):1056-1061. Exposure of Americans to polybrominated diphenyl ethers. Journal of Exposure Science and Environmental Epidemiology 2008;18(1):2-19. Epigenetic transgenerational actions of endocrine disrupters and mate fertility. Science 2005;308(5727): 1466-1469. Table 12. Number of Extremely Highly Cited EDCs Papers by Field (top 0.01%) ESI Field Environment/Ecology Multidisciplinary No. of Citations 14 259 Total = 273 No. of Papers 1 1 Total = 2 Average Cites/Paper 14.0 259.0 136.5 % of EPA Papers in Field 0.5% 10.0% 0.3% Table 13. Extremely Hi ESI Field Environment/ Ecology No. of Cites 14 First Author Lorber M ghly Cited EDCs Papers (top 0.01%) Paper Exposure of Americans to polybrominated diphenyl ethers. Journal of Exposure Science and Environmental Epidemiology 2008;18(1):2-19. ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 ESI Field Multidisciplinary No. of Cites 259 First Author Anway MD Paper Epigenetic transgenerational actions of endocrine disrupters and mate fertility. Science 2005;308(5727): 1466-1469. Ratio of Actual Cites to Expected Citation Rates The expected citation rate is the average number of cites that a paper published in the same journal in the same year and of the same document type (article, review, editorial, etc.) has received from the year of publication to the present. Using the ESI average citation rates for papers published by field as the benchmark, in 12 of the 16 fields in which the EPA EDCs papers were published, the ratio of actual to expected cites is greater than 1, indicating that the EDCs papers are more highly cited than the average papers in those fields (see Table 14). For all 16 fields combined, the ratio of total number of cites to the total number of expected cites (12,895 to 6,667) is 1.9, indicating that the EDCs papers are more highly cited than the average paper. Table 14. Ratio of Actual Cites to Expected Cites for EDCs Papers by Field ESI Field Agricultural Sciences Biology & Biochemistry Chemistry Clinical Medicine Computer Science Engineering Environment/Ecology Geosciences Mathematics Microbiology Molecular Biology & Genetics Multidisciplinary Neuroscience & Behavior Pharmacology & Toxicology Plant & Animal Science Social Sciences, general TOTAL Total Cites 26 1,390 398 1,626 3 29 3,362 7 0 1 64 1,100 274 3,582 1,007 26 12,895 Expected Cite Rate 15 1,164 292 922 1 13 1,622 6 0.1 3 130 48 456 1,507 480 8 6,667 Ratio 1.7 1.2 1.4 1.8 3.0 2.2 2.1 1.2 0 0.3 0.5 22.9 0.6 2.4 2.1 3.2 1.9 ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 JCR Benchmarks Impact Factor. The JCR Impact Factor is a well known metric in citation analysis. It is a measure of the frequency with which the "average article" in a journal has been cited in a particular year. The Impact Factor helps evaluate a journal's relative importance, especially when compared to others in the same field. The Impact Factor is calculated by dividing the number of citations in the current year to articles published in the 2 previous years by the total number of articles published in the 2 previous years. Table 15 indicates the number ofEDCs papers published in the top 10% of journals, based on the JCR Impact Factor. Two hundred seventy-two (272) of 652 papers were published in the top 10% of journals, representing 41.7% of EPA's EDCs papers. This indicates that nearly one-half of the EDCs papers are published in the highest quality journals as determined by the JCR Impact Factor, which is 4.2 times higher than the expected percentage. Table 15. EDCs Papers in Top 10% of Journals by JCR Impact Factor EPA EDCs Papers in that Journal 1 1 1 6 1 1 1 1 1 41 1 7 1 3 1 15 1 13 Journal New England Journal of Medicine Science British Medical Journal Proceedings of the National Academy of Sciences of the United States of America Cancer Research Development Human Reproduction Update Nucleic Acids Research Hippocampus Environmental Health Perspectives Journal of Clinical Endocrinology and Metabolism Analytical Chemistry American Journal of Epidemiology Epidemiology Molecular Ecology Critical Reviews in Toxicology Lab on a Chip Endocrinology Impact Factor (IF) 52.589 26.372 9.723 9.598 7.672 7.293 7.257 6.954 5.745 5.636 5.493 5.287 5.285 5.283 5.169 5.145 5.068 5.045 JCR IF Rank 2 14 109 114 164 182 185 194 272 279 290 309 310 311 326 330 335 339 10 ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 EPA EDCs Papers in that Journal 2 1 1 1 4 1 22 1 1 2 9 87 1 1 19 1 1 1 1 4 2 1 3 1 1 3 3 Total = 272 Journal Bioinformatics Journal of Medicinal Chemistry Cancer Epidemiology Biomarkers & Prevention Cancer Pediatrics Tissue Engineering Environmental Science & Technology BMC Genomics Applied and Environmental Microbiology Environmental Science and Pollution Research Toxicology and Applied Pharmacology Toxicological Sciences Evolution & Development European Journal of Neuroscience Biology of Reproduction Journal of Chromatography A American Journal of Public Health Electrophoresis Journal of Raman Spectroscopy Chemical Research in Toxicology BMC Bioinformatics Physiological Genomics Hormones and Behavior Neuroscience ATLA-Alternatives to Laboratory Animals Analytica Chimica Acta Fertility and Sterility Impact Factor (IF) 5.039 4.895 4.642 4.632 4.473 4.409 4.363 4.180 4.004 3.894 3.846 3.814 3.733 3.673 3.670 3.641 3.612 3.609 3.514 3.508 3.493 3.493 3.401 3.352 3.203 3.186 3.168 JCR IF Rank 340 359 405 408 435 456 465 514 571 598 614 622 659 680 682 695 709 710 744 745 756 756 782 815 871 877 883 11 ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 Immediacy Index. The JCR Immediacy Index is a measure of how quickly the average article in a journal is cited. It indicates how often articles published in a journal are cited within the year they are published. The Immediacy Index is calculated by dividing the number of citations to articles published in a given year by the number of articles published in that year. Table 16 indicates the number ofEDCs papers published in the top 10% of journals, based on the JCR Immediacy Index. One hundred eighty-four (184) of the 652 journal articles appear in the top 10% of journals, representing 28.2% of the EDCs papers. This indicates that more than one-quarter of the EDCs papers are published in the highest quality journals as determined by the JCR Immediacy Index, which is 2.8 times higher than the expected percentage. Table 16. EDCs Papers in Top 10% of Journals by JCR Immediacy Index EPA EDCs Papers in that Journal 1 1 1 6 3 2 1 1 1 1 1 1 13 1 2 1 41 7 2 1 Journal New England Journal of Medicine Science British Medical Journal Proceedings of the National Academy of Sciences of the United States of America Epidemiology ILAR Journal Nucleic Acids Research Development American Journal of Public Health Human Reproduction Update Lab on a Chip Journal of Clinical Endocrinology and Metabolism Endocrinology Cancer Research Environmental Science and Pollution American Journal of Epidemiology Environmental Health Perspectives Analytical Chemistry Reviews of Environmental Contamination and Toxicology Cancer Immediacy Index (II) 11.962 6.387 6.210 1.724 1.623 1.594 1.589 1.462 1.337 1.319 1.241 1.221 1.137 1.131 1.120 1.087 0.958 0.911 0.857 0.824 JCR 11 Rank 2 15 18 136 152 159 160 194 226 231 265 271 299 304 311 329 425 471 527 554 12 ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 EPA EDCs Papers in that Journal 4 1 1 1 1 1 1 19 1 1 1 4 3 1 2 3 1 1 9 1 16 1 22 Total = 184 Journal Pediatrics Journal of Medicinal Chemistry Ambio Journal of Environmental Monitoring Experimental Gerontology Molecular Ecology Evolution & Development Biology of Reproduction Journal of Experimental Biology Cancer Epidemiology Biomarkers & Prevention Physiological Genomics Environmental Pollution Fertility and Sterility Reproduction Fertility and Development Molecular and Cellular Endocrinology SAR and QSAR in Environmental Research Molecular Reproduction and Development Hippocampus Reproductive Toxicology Environment International Environmental Research Neuroscience Environmental Science & Technology Immediacy Index (II) 0.820 0.789 0.777 0.763 0.761 0.732 0.731 0.723 0.722 0.705 0.705 0.699 0.694 0.686 0.682 0.674 0.670 0.655 0.655 0.639 0.632 0.627 0.615 JCRll Rank 557 594 610 625 626 663 665 675 678 702 702 716 726 739 746 765 771 800 800 834 845 856 876 Hot Papers ESI establishes citation thresholds for hot papers, which are selected from the highly cited papers in different fields, but the time frame for citing and cited papers is much shorter—papers must be cited within 2 years of publication and the citations must occur in a 2-month time period. Papers are assigned to 2-month periods and thresholds are set for each period and field to select 0.1% of papers. 13 ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 Using the hot paper thresholds established by ESI as a benchmark, 6 hot papers, representing 0.9% of the EDCs papers, were identified in three fields—Environment/Ecology, Multidisciplinary, and Pharmacology & Toxicology. The number ofEDCs hot papers is 9 times higher than expected. The hot papers are listed in Table 17. Table 17. Hot Papers Identified Using ESI Thresholds Field Environment/ Ecology Multidisciplinary Pharmacology & Toxicology ESI Hot Papers Threshold 3 6 6 10 10 3 No. of Cites in 2-Month Period 6 cites in February- March 2007 6 cites in September- October 2008 12 cites in February- March 2006 19 cites in May-June 2006 10 cites in February- March 2004 3 cites in January 2006 Paper LeBlanc GA. Crustacean endocrine toxicology: a review. Ecotox/co/ogy2007;16(l):61-81. Lorber M. Exposure of Americans to polybrominated diphenyl ethers. Journal of Exposure Science and Environmental Epidemiology 2008;18(1):2-19. Swan SH, et al. Decrease in anogenital distance among male infants with prenatal phthalate exposure. Environmental Health Perspectives 2005;! 13(8): 1056-1061. Anway MD, et al. Epigenetic transgenerational actions of endocrine disrupters and male fertility. Science 2005;308(5727): 1466-1469. Zhu Y, et al. Cloning, expression, and characterization of a membrane progestin receptor and evidence it is an intermediary in meiotic maturation offish oocytes. Proceedings of the National Academy of Sciences of the United States of America 2003; 100(5):223 1-2236. Carmichael NG, et al. Agricultural chemical safety assessment: a multisector approach to the modernization of human safety requirements. Critical Reviews in Toxicology 2006;36(l):l-7. Author Self-Citation Self-citations are journal article references to articles from that same author (i.e., the first author). Because higher author self-citation rates can inflate the number of citations, the author self-citation rate was calculated for the EDCs papers. Of the 12,895 total cites, 544 are author self-cites—a 4.2% author self-citation rate. Garfield and Sher3 found that authors working in research-based disciplines tend to cite themselves on the average of 20% of the time. MacRoberts and MacRoberts4 claim that approximately 10% to 30% of all the citations listed fall into the category of author self-citation. 3 Garfield E, Sher IH. New factors in the evaluation of scientific literature through citation indexing. American Documentation 1963;18(July):195-210. 4 MacRoberts MH, MacRoberts BR. Problems of citation analysis: a critical review. Journal of the American Society of Information Science 1989;40(5):342-349. 14 ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 Kovacic and Misak5 recently reported a 20% author self-citation rate for medical literature. Therefore, the 4.2% self-cite rate for the EDCs papers is well below the range for author self-citation. Highly Cited Researchers A search of Thomson's ISIHighlyCited. com revealed that 21 (1.5%) of the 1,379 authors of the EDCs papers are highly cited researchers. ISIHighlyCited.com is a database of the world's most influential researchers who have made key contributions to science and technology during the period from 1981 to 1999. The highly cited researchers identified during this analysis of the EDCs publications are presented in Table 18. Table 18. Highly Cited Researchers Authoring EDCs Publications Highly Cited Researcher Andersen, Melvin E. Ankley, Gerald Birnbaum, Linda S. Boobis, Alan R. Brown, Sandra Burger, Joanna German, J. Bruce Giesy, John P. Guillette, Louis J. Jobling, Susan Klaassen, Curtis D. McLachlan, John A. Needham, Larry L. Rao, P. Suresh Chandra Sih, Andrew Soto, Ana M. Starfield, Barbara Stegeman, John J. Affiliation CUT Centers for Health Research U.S. Environmental Protection Agency U.S. Environmental Protection Agency Imperial College London Winrock International Rutgers University University of California-Davis University of Saskatchewan University of Florida University of Brunei University of Kansas Medical Center Tulane University National Center for Environmental Health Purdue University University of California-Davis Tufts University The Johns Hopkins University Woods Hole Oceanographic Institution ESI Field Pharmacology Environment/Ecology Pharmacology Pharmacology Environment/Ecology Environment/Ecology Agricultural Sciences Environment/Ecology Environment/Ecology Environment/Ecology Pharmacology Environment/Ecology Environment/Ecology Environment/Ecology Environment/Ecology Environment/Ecology Pharmacology Social Sciences, general Pharmacology Kavaci N, Misak A. Author self-citation in medical literature. Canadian Medical Association Journal 2004;170(13):1929-1930. 15 ------- Bibliometric Analysis ofEDCs Research Program Journal Articles—February 2009 Highly Cited Researcher Suidan, Makram T. Sumpter, John P. Wright, S. Joseph Total = 21 Affiliation University of Cincinnati Brunei University Smithsonian Tropical Research Institute ESI Field Environment/Ecology Environment/Ecology Environment/Ecology Patents No patents have been issued or patent applications filed by investigators from 1998 to 2008 for research that was conducted under EPA's EDCs Research Program. Nonjournal Publications (Books, Book Chapters, Reports, and Proceedings) Forty-six nonjournal publications (books, book chapters, reports, and proceedings) produced by the program from 1998 to 2008 were included in the analysis. Of these 46 nonjournal publications, 20 (43.5%) have been cited at least once in a journal. The 46 publications were cited 180 times in the journals covered by Thomson Reuter's 757 Web of Science. The authors of the nonjournal publications cited themselves 9 times, a 5.0% self citation rate, which is well below the 10-30% range report in the literature for author self-citation. Application of the ESI fields and highly cited benchmarks used for journal papers to the nonjournal publications, indicated that 2 (4.4%) of the nonjournal publications were highly cited when using the ESI criteria for the top 10% of highly cited publications. None of the nonjournal publications met the ESI criteria for the top 1%, 0.1%, or 0.01% highly cited publications. This bibliometric analysis was prepared by Beverly Campbell of The Scientific Consulting Group, Inc. in Gaithersburg, Maryland under EPA Contract No. EP-C-05-015 16 ------- |