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2009 Bibliometric Analysis for the U.S. Environmental Protection Agency/Office of Research and Developments Endocrine Disrupting Chemicals (EDCs) Research Program
February 2009

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.

SUMMARY OF RESULTS
  1. 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 ESI 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 ESI 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 JCR 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 JCR 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.

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.

Table 1. EDCs Papers by ESI Fields

ESI Field

No. of Citations

No. of EPA Papers

Average Cites/Paper

Agricultural Sciences

26

3

8.7

Biology & Biochemistry

1,390

79

17.6

Chemistry

398

36

11.0

Clinical Medicine

1,626

74

22.0

Computer Science

3

2

1.5

Engineering

29

5

5.8

Environment/Ecology

3,362

195

17.2

Geosciences

7

1

7.0

Mathematics

0

1

0

Microbiology

1

1

1.0

Molecular Biology & Genetics

64

7

9.1

Multidisciplinary

1,100

10

110.0

Neuroscience & Behavior

274

26

10.5

Pharmacology & Toxicology

3,582

138

26.0

Plant & Animal Science

1,007

72

14.0

Social Sciences, general

26

2

13.0

 

Total = 12,895

Total = 652

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% 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

No. of Citations

No. of Papers

Average Cites/Paper

% of Papers in Field

Agricultural Sciences

21

1

21.0

33.3%

Biology & Biochemistry

506

16

31.6

20.2%

Chemistry

183

5

36.6

13.9%

Clinical Medicine

940

21

44.8

28.4%

Computer Science

3

1

3.0

50.0%

Engineering

24

2

12.0

40.0%

Environment/Ecology

2,077

56

37.1

28.7%

Multidisciplinary

1,080

7

154.3

70.0%

Neuroscience & Behavior

11

1

11.0

3.8%

Pharmacology & Toxicology

2,539

44

57.7

31.9%

Plant & Animal Science

779

26

30.0

36.1%

Social Sciences, general

17

1

17.0

50.0%

 

Total =  8,180

Total = 181 

45.2

27.8%

 

Table 3. Number of Highly Cited EDCs Papers by Field (top 1%)

ESI Field

No. of Citations

No. of Papers

Average Cites/Paper

% of EPA Papers in Field

Biology & Biochemistry

47

1

47.0

1.3%

Clinical Medicine

213

4

53.2

5.4%

Engineering

22

1

22.0

20.0%

Environment/Ecology

632

9

70.2

4.6%

Multidisciplinary

1,027

6

171.2

60.0%

Pharmacology & Toxicology

841

6

140.2

4.4%

 

Total = 2,782

Total = 27

103.0

4.1%

Table 4. Highly Cited EDCs Papers in the Field of Biology & Biochemistry (top 1%)

No. of Cites

First Author

Paper

47

Anway MD

Epigenetic transgenerational actions of endocrine disruptors. Endocrinology 2006;147(6):S43-S49.

Table 5. Highly Cited EDCs Papers in the Field of Clinical Medicine (top 1%)

No. of Cites

First Author

Paper

151

Gray LE

Effects of environmental antiandrogens on reproductive development in experimental animals.  Human Reproduction Update 2001;7(3):248-264.

48

Gray LE

Adverse effects of environmental antiandrogens and androgens on reproductive development in mammals.  International Journal of Andrology 2006;29(1):96-104.

6

Euling SY

Examination of US puberty-timing data from 1940 to 1994 for secular trends: Panel findings.  Pediatrics 2008;121:S172-S191.

8

Rider CV

A mixture of seven antiandrogens induces reproductive malformations in rats.  International Journal of Andrology 2008;31(2):249-262.

Table 6. Highly Cited EDCs Papers in the Field of Engineering (top 1%)

No. of Cites

First Author

Paper

22

De Jesus MA

Nanofabrication of densely packed metal-polymer arrays for surface-enhanced Raman spectrometry.  Applied Spectroscopy 2005;59(12):1501-1508.

Table 7. Highly Cited EDCs Papers in the Field of Environment/Ecology (top 1%)

No. of Cites

First Author

Paper

187

Crisp TM

Environmental endocrine disruption:  an effects assessment and analysis.  Environmental Health Perspectives 1998;106(Suppl 1):11-56.

130

Ankley GT

Description and evaluation of a short-term reproduction test with the fathead minnow (Pimephales promelas).  Environmental Toxicology and Chemistry 2001;20(6):1276-1290.

48

Mills LJ

Review of evidence:  are endocrine-disrupting chemicals in the aquatic environment impacting fish populations?  Science of the Total Environment 2005;343(1-3):1-34.

186

Swan SH

Decrease in anogenital distance among male infants with prenatal phthalate exposure.  Environmental Health Perspectives 2005;113(8):1056-1061.

18

LeBlanc GA

Crustacean endocrine toxicology: a review.  Ecotoxicology 2007;16(1):61-81.

18

Villeneuve DL

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.

26

Mergler D

Methylmercury exposure and health effects in humans:  a worldwide concern.  Ambio 2007;36(1):3-11.

5

Kostich MS

Risks to aquatic organisms posed by human pharmaceutical use.  Science of the Total Environment 2008;389(2-3):329-339.

14

Lorber M

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

Zhu Y

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.

252

Zhu Y

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.

69

Timms BG

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.

259

Anway MD

Epigenetic transgenerational actions of endocrine disruptors and mate fertility.  Science 2005;308(5727):1466-1469. 

39

Kidd KA

Collapse of a fish population after exposure to a synthetic estrogen.  Proceedings of the National Academy of Sciences of the United States of America 2007;104(21):8897-8901.

Table 9.  Highly Cited EDCs Papers in the Field of Pharmacology & Toxicology (top 1%)

No. of Cites

First Author

Paper

195

Parks LG

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.

209

Laws SC

Estrogenic activity of octylphenol, nonylphenol, bisphenol A and methoxychlor in rats.  Toxicological Sciences 2000;54(1):154-167.

217

Gray LE

Perinatal exposure to the phthalates DEHP, BBP, and DINP, but not DEP, DMP, or DOTP, alters sexual differentiation of the male rat.  Toxicological Sciences 2000;58(2):350-365.

126

Zhou T

Developmental exposure to brominated diphenyl ethers results in thyroid hormone disruption.  Toxicological Sciences 2002;66(1):105-116.

89

Wilson VS

Phthalate ester-induced gubernacular lesions are associated with reduced insl3 gene expression in the fetal rat testis.  Toxicology Letters 2004;146(3):207-215.

5

Richardson VM

Possible mechanisms of thyroid hormone disruption in mice by BDE 47, a major polybrominated diphenyl ether congener.  Toxicology and Applied Pharmacology 2008;226(3):244-250.

Table 10. Number of Very Highly Cited EDCs Papers by Field (top 0.1%)

ESI Field

No. of Citations

No. of Papers

Average Cites/Paper

% of EPA Papers in Field

Environment/Ecology

200

2

100.0

1.0%

Multidisciplinary

259

1

259.0

10.0%

 

Total = 459

Total = 3

153.0

0.5%

Table 11.  Very Highly Cited EDCs Papers (top 0.1%)

ESI Field

No. of Cites

First Author

Paper

Environment/ Ecology

186

Swan SH

Decrease in anogenital distance among male infants with prenatal phthalate exposure.  Environmental Health Perspectives 2005;113(8):1056-1061.

 

14

Lorber M

Exposure of Americans to polybrominated diphenyl ethers.  Journal of Exposure Science and Environmental Epidemiology 2008;18(1):2-19.

Multidisciplinary

259

Anway MD

Epigenetic transgenerational actions of endocrine disruptors 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

No. of Citations

No. of Papers

Average Cites/Paper

% of EPA Papers in Field

Environment/Ecology

14

1

14.0

0.5%

Multidisciplinary

259

1

259.0

10.0%

 

Total = 273

Total = 2

136.5

0.3%

Table 13.  Extremely Highly Cited EDCs Papers (top 0.01%)

ESI Field

No. of Cites

First Author

Paper

Environment/ Ecology

14

Lorber M

Exposure of Americans to polybrominated diphenyl ethers.  Journal of Exposure Science and Environmental Epidemiology 2008;18(1):2-19.

Multidisciplinary

259

Anway MD

Epigenetic transgenerational actions of endocrine disruptors 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

Total Cites

Expected Cite Rate

Ratio

Agricultural Sciences

26

15

1.7

Biology & Biochemistry

1,390

1,164

1.2

Chemistry

398

292

1.4

Clinical Medicine

1,626

922

1.8

Computer Science

3

1

3.0

Engineering

29

13

2.2

Environment/Ecology

3,362

1,622

2.1

Geosciences

7

6

1.2

Mathematics

0

0.1

0

Microbiology

1

3

0.3

Molecular Biology & Genetics

64

130

0.5

Multidisciplinary

1,100

48

22.9

Neuroscience & Behavior

274

456

0.6

Pharmacology & Toxicology

3,582

1,507

2.4

Plant & Animal Science

1,007

480

2.1

Social Sciences, general

26

8

3.2

TOTAL

12,895

6,667

1.9

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 of EDCs 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

Journal

Impact Factor
(IF)

JCR IF Rank

1

New England Journal of Medicine

52.589

2

1

Science

26.372

14

1

British Medical Journal

9.723

109

6

Proceedings of the National Academy of Sciences of the United States of America

9.598

114

1

Cancer Research

7.672

164

1

Development

7.293

182

1

Human Reproduction Update

7.257

185

1

Nucleic Acids Research

6.954

194

1

Hippocampus

5.745

272

41

Environmental Health Perspectives

5.636

279

1

Journal of Clinical Endocrinology and Metabolism

5.493

290

7

Analytical Chemistry

5.287

309

1

American Journal of Epidemiology

5.285

310

3

Epidemiology

5.283

311

1

Molecular Ecology

5.169

326

15

Critical Reviews in Toxicology

5.145

330

1

Lab on a Chip

5.068

335

13

Endocrinology

5.045

339

2

Bioinformatics

5.039

340

1

Journal of Medicinal Chemistry

4.895

359

1

Cancer Epidemiology Biomarkers & Prevention

4.642

405

1

Cancer

4.632

408

4

Pediatrics

4.473

435

1

Tissue Engineering

4.409

456

22

Environmental Science & Technology

4.363

465

1

BMC Genomics

4.180

514

1

Applied and Environmental Microbiology

4.004

571

2

Environmental Science and Pollution Research

3.894

598

9

Toxicology and Applied Pharmacology

3.846

614

87

Toxicological Sciences

3.814

622

1

Evolution & Development

3.733

659

1

European Journal of Neuroscience

3.673

680

19

Biology of Reproduction

3.670

682

1

Journal of Chromatography A

3.641

695

1

American Journal of Public Health

3.612

709

1

Electrophoresis

3.609

710

1

 Journal of Raman Spectroscopy

3.514

744

4

Chemical Research in Toxicology

3.508

745

2

BMC Bioinformatics

3.493

756

1

Physiological Genomics

3.493

756

3

Hormones and Behavior

3.401

782

1

Neuroscience

3.352

815

1

ATLA-Alternatives to Laboratory Animals

3.203

871

3

Analytica Chimica Acta

3.186

877

3

Fertility and Sterility

3.168

883

Total = 272

                                                                                            

 

 

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 of EDCs 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

Journal

Immediacy Index
(II)

JCR II Rank

1

New England Journal of Medicine

11.962

2

1

Science

6.387

15

1

British Medical Journal

6.210

18

6

Proceedings of the National Academy of Sciences of the United States of America

1.724

136

3

Epidemiology

1.623

152

2

ILAR Journal

1.594

159

1

Nucleic Acids Research

1.589

160

1

Development

1.462

194

1

American Journal of Public Health

1.337

226

1

Human Reproduction Update

1.319

231

1

Lab on a Chip

1.241

265

1

Journal of Clinical Endocrinology and Metabolism

1.221

271

13

Endocrinology

1.137

299

1

Cancer Research

1.131

304

2

Environmental Science and Pollution

1.120

311

1

American Journal of Epidemiology

1.087

329

41

Environmental Health Perspectives

0.958

425

7

Analytical Chemistry

0.911

471

2

Reviews of Environmental Contamination and Toxicology

0.857

527

1

Cancer

0.824

554

4

Pediatrics

0.820

557

1

Journal of Medicinal Chemistry

0.789

594

1

Ambio

0.777

610

1

Journal of Environmental Monitoring

0.763

625

1

Experimental Gerontology

0.761

626

1

Molecular Ecology

0.732

663

1

Evolution & Development

0.731

665

19

Biology of Reproduction

0.723

675

1

Journal of Experimental Biology

0.722

678

1

Cancer Epidemiology Biomarkers & Prevention

0.705

702

1

Physiological Genomics

0.705

702

4

Environmental Pollution

0.699

716

3

Fertility and Sterility

0.694

726

1

Reproduction Fertility and Development

0.686

739

2

Molecular and Cellular Endocrinology

0.682

746

3

SAR and QSAR in Environmental Research

0.674

765

1

Molecular Reproduction and Development

0.670

771

1

Hippocampus

0.655

800

9

Reproductive Toxicology

0.655

800

1

Environment International

0.639

834

16

Environmental Research

0.632

845

1

Neuroscience

0.627

856

22

Environmental Science & Technology

0.615

876

Total = 184

 

 

 

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.  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 of EDCs 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

ESI Hot Papers Threshold

No. of Cites in 2-Month Period

Paper

Environment/ Ecology

3

6 cites in February-March 2007

LeBlanc GA.  Crustacean endocrine toxicology:  a review.  Ecotoxicology 2007;16(1):61-81.

 

6

6 cites in September-October 2008

Lorber M.  Exposure of Americans to polybrominated diphenyl ethers.  Journal of Exposure Science and Environmental Epidemiology 2008;18(1):2-19.

 

6

12 cites in February-March 2006

Swan SH, et al.  Decrease in anogenital distance among male infants with prenatal phthalate exposure.  Environmental Health Perspectives 2005;113(8):1056-1061.

Multidisciplinary

10

19 cites in May-June 2006

Anway MD, et al.  Epigenetic transgenerational actions of endocrine disruptors and male fertility.  Science 2005;308(5727):1466-1469.

 

10

10 cites in February-March 2004

Zhu Y, et al.  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.

Pharmacology & Toxicology

3

3 cites in January 2006

Carmichael NG, et al.  Agricultural chemical safety assessment:  a multisector approach to the modernization of human safety requirements.  Critical Reviews in Toxicology 2006;36(1):1-7.

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. 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

Affiliation

ESI Field

Andersen, Melvin E.

CIIT Centers for Health Research

Pharmacology

Ankley, Gerald

U.S. Environmental Protection Agency

Environment/Ecology

Birnbaum, Linda S.

U.S. Environmental Protection Agency

Pharmacology

Boobis, Alan R.

Imperial College London

Pharmacology

Brown, Sandra

Winrock International

Environment/Ecology

Burger, Joanna

Rutgers University

Environment/Ecology

German, J. Bruce

University of California-Davis

Agricultural Sciences

Giesy, John P.

University of Saskatchewan

Environment/Ecology

Guillette, Louis J.

University of Florida

Environment/Ecology

Jobling, Susan

University of Brunel

Environment/Ecology

Klaassen, Curtis D.

University of Kansas Medical Center

Pharmacology

McLachlan, John A.

Tulane University

Environment/Ecology

Needham, Larry L.

National Center for Environmental Health

Environment/Ecology

Rao, P. Suresh Chandra

Purdue University

Environment/Ecology

Sih, Andrew

University of California–Davis

Environment/Ecology

Soto, Ana M.

Tufts University

Environment/Ecology
Pharmacology

Starfield, Barbara

The Johns Hopkins University

Social Sciences, general

Stegeman, John J.

Woods Hole Oceanographic Institution

Pharmacology

Suidan, Makram T.

University of Cincinnati

Environment/Ecology

Sumpter, John P.

Brunel University

Environment/Ecology

Wright, S. Joseph

Smithsonian Tropical Research Institute

Environment/Ecology

Total = 21

 

 

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 ISI 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.

1Thomson 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.

2Scopus 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.

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.

5 Kavaci N, Misak A. Author self-citation in medical literature. Canadian Medical Association Journal 2004;170(13):1929-1930.

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