Coverage of Author Identifiers in Web of Science and Scopus

03/03/2017
by   Thomas Krämer, et al.
0

As digital collections of scientific literature are widespread and used frequently in knowledge-intense working environments, it has become a challenge to identify author names correctly. The treatment of homonyms is crucial for the reliable resolution of author names. Apart from varying handling of first, middle and last names, vendors as well as the digital library community created tools to address the problem of author name disambiguation. This technical report focuses on two widespread collections of scientific literature, Web of Science (WoS) and Scopus, and the coverage with author identification information such as Researcher ID, ORCID and Scopus Author Identifier in the period 1996 - 2014. The goal of this study is to describe the significant differences of the two collections with respect to overall distribution of author identifiers and its use across different subject domains. We found that the STM disciplines show the best coverage of author identifiers in our dataset of 6,032,000 publications which are both covered by WoS and Scopus. In our dataset we found 184,823 distinct ResearcherIDs and 70,043 distinct ORCIDs. In the appendix of this report we list a complete overview of all WoS subject areas and the amount of author identifiers in these subject areas.

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Coverage of Author Identifiers in Web of Science and Scopus

Thomas Krämer111Corresponding author: thomas.kraemer@gesis.org, Fakhri Momeni, Philipp Mayr

GESIS – Leibniz-Institute for the Social Sciences, Cologne, Germany

Abstract

As digital collections of scientific literature are widespread and used frequently in knowledge-intense working environments, it has become a challenge to identify author names correctly. The treatment of homonyms is crucial for the reliable resolution of author names. Apart from varying handling of first, middle and last names, vendors as well as the digital library community created tools to address the problem of author name disambiguation. This technical report focuses on two widespread collections of scientific literature, Web of Science (WoS) and Scopus, and the coverage with author identification information such as Researcher ID, ORCID and Scopus Author Identifier in the period 1996 - 2014. The goal of this study is to describe the significant differences of the two collections with respect to overall distribution of author identifiers and its use across different subject domains. We found that the STM disciplines show the best coverage of author identifiers in our dataset of 6,032,000 publications which are both covered by WoS and Scopus. In our dataset we found 184,823 distinct ResearcherIDs and 70,043 distinct ORCIDs. In the appendix of this report we list a complete overview of all WoS subject areas and the amount of author identifiers in these subject areas.

Keywords: Disambiguation; author name homonyms; author identification; citation databases; WoS subject areas; Researcher ID; ORCID; Scopus Author Identifier

1 Introduction

The role of unique identifiers in the scientific publishing infrastructure is becoming more and more important Kraker et al. (2015). Especially author identifiers Warner (2010) play a crucial role in bibliometric research and other searching and harvesting activities.

Author name disambiguation has an important effect on bibliometric analysis Reijnhoudt et al. (2013); Ioannidis et al. (2014), scholarly networks Kim et al. (2015) and all other scientometric approches using large-scale bibliographic data Mutschke and Mayr (2015). Therefore an author identification system with a high accuracy is vital for the further processing on bibliometric data. Harzing Harzing (2015) explains how frequency of homonym names in Thomson Reuter’s Essential Science Indicators can be problematic. Also, Torvik and Smalheiser Torvik and Smalheiser (2009) mentioned that accuracy of author disambiguation depends on name frequency and common names tend to be harder to disambiguate. Kawashima and Tomizawa Kawashima and Tomizawa (2015)

evaluated the accuracy of Scopus author identifier based on the largest funding database in Japan. They got a high precision and recall, but they noted the dependency of author ID accuracy on country or language.

Several approaches exist to address the systemic name ambiguity problems in research publications: automated or analytical procedures that apply algorithms to publication metadata to identify and group publications of the same author as well as manual approaches that require author interaction to claim or verify authorship De Cock et al. (2013). Three recent surveys about author name disambiguation have been presented in the literature Ferreira et al. (2012); Elliott (2010); Smalheiser and Torvik (2009). In these surveys the basic problems of author name disambiguation are outlined and the most popular methods are overviewed.

Researchers can register their ResearcherID by self-registration either as subscribers of Web of Science or at the ResearcherID website222http://www.researcherid.com/. The link between documents in Web of Science and ResearcherIDs is established by means of a publication list: Authors themselves add publications to their profile and thus connect their ResearcherID with the publication metadata in Web of Science.

In Scopus, Scopus Author Identifiers are assigned automatically. The algorithm groups author names under a common Scopus Author Identifier based on an algorithm that matches affiliation, address, subject area, source title, dates of publication citations, and co-authors information Elsevier (2016). However, the exact matching procedure of Scopus is not known. ResearcherID and Scopus Author Identifier are integrated into their respective digital libraries, Web of Science resp. Scopus.

Independent from these two systems, ORCID333http://orcid.org/ is an open system designed for author identification Haak et al. (2012). The system started in 2012 and is operated by a non-for-profit organization whose members are commercial as well as educational institutions. Similar to ResearcherID, authors register themselves and receive an identifier which then should be used whenever work is submitted for publication. A couple of journals (e.g. published with Springer or PLOS) use the ORCID identifier already in the submission process of a manuscript and publish the ORCID together with the other author information.

In this technical report we describe the existence of three prominent author identifiers (ResearcherID, ORCID and Scopus Author Identifier) Fenner et al. (2011) in a joint subset of the Web of Science and Scopus. We will report about the gaps in coverage in different WoS subject areas. Finally we will try to show the effect of author name homonyms on the distribution of ORCIDs (orcid), ResearcherIDs (rid) and Scopus Author identifiers (Scopus).

2 Dataset

The Competence Centre for Bibliometrics444http://www.bibliometrie.info/ in Germany has access to the raw data exports of Scopus and Web of Science from January 1996 to April 2014. Based on the raw exports, Leibniz Institute for Information Infrastructure (FIZ Karlsruhe)555https://www.fiz-karlsruhe.de/en.html has created an infrastructure for bibliometric analyses that contains standardized representations of both collections. This infrastructure provides a duplicate database666Here, duplicate denotes publications that are present in both WoS and Scopus database while Valderrama-Zurián et al. (2015) conducted duplicate record detection within Scopus metadata. that maps pairs of identical publications. FIZ Karlsruhe automatically identified duplicates by pairwise comparisons of WoS and Scopus metadata. Each pair was checked multiple times, applying different properties to be compared (see Table 1). We decided to use a rather strict criterion to define the common subset for our analysis in order to achieve two standardized, nearly identical samples of publications in both collections. We set a minimum threshold of 317 (compare Table 1) to fetch documents from both collections. We consider pairs of metadata from WoS and Scopus describing an identical publication only if the DOI and two or more other metadata fields match in both records. Other fields are publisher item identifier, issue, publication year, volume, ISSN, first page, first author or title. Applying these criteria we got a dataset that consists of pairs of metadata describing approximately 6,032,000 publications which are both covered by WoS and Scopus.

weight criteria
93 Title, 1.Page, ISSN, Volume, Issue
317 DOI, 1.Author, 1.Page, ISSN, Volume, Issue
509 DOI, PII, Title, 1.Author, 1.Page, ISSN, Volume, Issue
Table 1: Weights assigned to pairs of metadata according to matching properties

A small difference (below 0.02%) in the number of publications indicates that the chosen criteria are appropriate to identify identical publications in the two collections.

3 Method

3.1 Comparing subject areas

We chose the WoS subject areas777http://incites.isiknowledge.com/common/help/h_field_category_wos.html as reference for the following comparison. As the duplicate database provides a reliable means to identify one specific document in both corpora, it is feasible to apply the subject areas of WoS to the same document in the Scopus database. We grouped all documents in our subset according to the publication year and the WoS subject areas that have been assigned to the same document.

3.2 Checking author homonyms

As another selection criteria we chose those first and last name pairs that have either an author id, an orcid or a researcher id assigned. We assumed that a large number of institutions and a very wide range of journals per identifiable author could be the result of incorrect author id assignment. For each first and last name pair with a single identifier of one of the three author id systems and a minimum number of 100 publications, we checked the distributions of institutions they have been affiliated to and the number of journals in which the related publication appeared.

4 Results

4.1 General coverage of author identifiers

Our analysis leads to 184,823 distinct ResearcherIDs (rid) and 70,043 distinct ORCIDs. In the Scopus data, we found 9,839,749 authors, out of which 9,839,711 (100 %) have a Scopus Author ID (authorid) assigned. The automatic assignment of Scopus Author Identifiers succeeded in nearly every document (see Table 3) in the subset, whereas the relative number of ResearcherIDs related to publications in recent years decreased steadily (see Table 2).

year authors in documents rid % rid orcid % orcid
2014 1,267,886 30,706 2.42 17,681 1.39
2013 6,207,543 213,368 3.44 111,535 1.80
2012 5,706,042 274,630 4.81 123,964 2.17
2011 5,083,237 294,323 5.79 119,752 2.36
2010 4,508,560 281,554 6.24 108,953 2.42
2009 4,052,351 278,685 6.88 105,504 2.60
2008 2,970,989 218,877 7.37 81,940 2.76
2007 250,397 18,946 7.57 7,305 2.92
2006 13,791 773 5.61 309 2.24
2005 6,640 393 5.92 157 2.36
2004 4,728 332 7.02 162 3.43
2003 2,198 120 5.46 57 2.59
2002 1,429 90 6.30 45 3.15
2001 1,162 99 8.52 42 3.61
2000 451 19 4.21 11 2.44
1999 102 4 3.92 2 1.96
1998 58 2 3.45 1 1.72
1997 90 10 11.11 4 4.44
1996 165 8 4.85 3 1.82
Table 2: ORCID and ResearcherIDs - yearly percentage 999The publication year 2014 includes data from January to April.
year authorid total % missing values
2014 1,262,894 1,262,894 100 0
2013 6,312,343 6,312,343 100 0
2012 5,929,758 5,929,758 100 0
2011 5,275,211 5,275,214 100 3
2010 4,704,713 4,704,715 100 2
2009 4,258,223 4,258,250 100 27
2008 3,093,222 3,093,228 100 6
2007 258,001 258,001 100 0
2006 14,673 14,673 100 0
2005 6,933 6,933 100 0
2004 4,865 4,865 100 0
2003 2,943 2,943 100 0
2002 1,494 1,494 100 0
2001 1,262 1,262 100 0
2000 466 466 100 0
1999 109 109 100 0
1998 108 108 100 0
1997 91 91 100 0
1996 169 169 100 0
Table 3: Scopus author ids - yearly percentage

4.2 Coverage in subject areas

We summed the absolute numbers of author ids (any system) present in the subset. Within the twenty most frequent subject areas, Scopus author identifiers are particularly dominant in medical domains such as ’oncology’, ’surgery’ or ’immunology’ (see Figure 1).

classification researcher id
Materials Science, Multidisciplinary 65,837
Chemistry, Physical 64,639
Physics, Applied 61,655
Chemistry, Multidisciplinary 52,875
Biochemistry & Molecular Biology 46,393
Physics, Condensed Matter 42,387
Nanoscience & Nanotechnology 39,123
Multidisciplinary Sciences 30,250
Environmental Sciences 29,394
Physics, Multidisciplinary 29,141
Table 4: Top 10 subject areas covered with researcher ids
classification orcid
Materials Science, Multidisciplinary 32,940
Chemistry, Physical 30,708
Physics, Applied 25,854
Chemistry, Multidisciplinary 25,382
Biochemistry & Molecular Biology 24,721
Physics, Condensed Matter 21,306
Multidisciplinary Sciences 19,002
Nanoscience & Nanotechnology 18,271
Environmental Sciences 17,694
Physics, Multidisciplinary 13,166
Table 5: Top 10 subject areas covered with orcids
classification Scopus author id
Biochemistry & Molecular Biology 1,256,720
Materials Science, Multidisciplinary 983,555
Physics, Applied 822,106
Multidisciplinary Sciences 820,757
Chemistry, Physical 798,542
Oncology 792,495
Chemistry, Multidisciplinary 747,621
Neurosciences 699,094
Pharmacology & Pharmacy 685,833
Cell Biology 664,492
Table 6: Top 10 subject areas covered with Scopus author ids

4.3 Identification of homonyms

The following tables show the total, average and maximum number for each system with author ids related to at least 100 publications in the subset101010

Please note that the descriptive statistics for publication (see Table

7), for institution (Table 9) and issue distribution (see Table 8) rely on the primary keys assigned to an institution resp. issue in the FIZ Karlsruhe bibliographic database..

orcid rid Scopus
total author ids 91 86 8,338
average publications per author 132.7 133.6 142.2
publications maximum 355 355 2,338
Table 7: Publications of supposed frequent authors

We found 91 authors with an ORCID, that have 100 or more publications, with 132.7 as average and 355 as the maximum. The Scopus data contains 8,338 authors that are each related to 100 or more publications, and one Scopus Author Identifier appearing in 2,338 publications (see Table 7).

The number of publications and journals of these supposed frequent writers are similar for related ResearcherIDs and ORCIDs.

orcid rid Scopus
author ids 90 81 8,219
appeared in journals average 115.1 115.5 118.4
appeared in journals maximum 329 329 2,322
Table 8: Journals in which supposed frequent writers appear

This does not apply to the number of institutions associated with these publications, which is less for ResearcherID.

For Scopus, all distributions have much higher maximum values, while the averages differ significantly for the institutions related to the supposed frequent writers: 8,219 Scopus Identifiers have 100 or more publications, that are related to 151.4 institutions on average (see Table 9).

orcid rid Scopus
author ids 90 81 8,219
affiliated with institutions average 98.6 87.0 151.4
affiliated with institutions maximum 1,417 344 5,364
Table 9: Institutions supposed frequent writers are associated with

For each of the three author identification systems, we chose ten authors that were related to the maximum number of publications. Tables 10 and 11 show a limitation of the automated procedure applied in Scopus: While the supposed top ten list of author names for ResearcherID and ORCID do contain Western as well as Asian names, the top ten Scopus Author Identifiers contain exclusively Asian names, which have a common Western transliteration.

first last orcid publications
PAUL K. CHU 0000-0002-5581-4883 355
ULRICH S. SCHUBERT 0000-0003-4978-4670 270
ABDULLAH M. ASIRI 0000-0001-7905-3209 210
KRZYSZTOF MATYJASZEWSKI 0000-0003-1960-3402 193
RICHARD D. SMITH 0000-0002-2381-2349 183
HIDEO HOSONO 0000-0001-9260-6728 179
AKIHISA INOUE 0000-0002-7546-5334 167
JINDE CAO 0000-0003-3133-7119 163
L. SCODELLARO 0000-0002-4974-8330 163
ANNE B. NEWMAN 0000-0002-0106-1150 160
Table 10: Names of 10 authors with highest publication count - orcid
first last author id publications
WEI WANG 7501761836 2,338
WEI LIU 36077269600 1,773
YAN WANG 8640586600 1,735
YING WANG 55757783062 1,448
WEI CHEN 9639099600 1,375
LI LI 55218828300 1,285
WEI WANG 36072896000 1,218
HUI LI 56002811300 1,198
QIANG WANG 35178491000 1,146
XI CHEN 8043429800 1,105
Table 11: Names of 10 authors with highest publication count - Scopus author identifier

5 Discussion and conclusions

In this report we compared Web of Science and Scopus with regard to different author identifier systems. Documents in WoS and Scopus were considered identical if DOI and at least two more criteria matched. This might introduce artifacts, as some disciplines might have adopted DOI assignment earlier than others and are therefore overrepresented.

ORCID and ResearcherID require human intervention while Scopus Author Identifier is assigned automatically. Comparing documents with a manually assigned identifier system, ResearcherID is assigned more often (70.5%) than ORCID (29.5%).

Asian name transliteration leads to common representations of originally distinct author names Wang (2015). This, in turn, results in a remarkable loss of precision of many automated author matching procedures Strotmann and Zhao (2012). Therefore, Scopus Author Identifier is not a reliable source for author assignments. Elsevier itself promotes the use of ORCID instead and offers the possibility to import publication metadata from Scopus to ORCID111111https://orcid.scopusfeedback.com/. Authors might sort out false positives during this step and help to improve the Scopus Author Identifier assignment.

The review of author identifiers and the assignment of classification terms points into the same direction. The manual approach ThomsonReuters chose with ResearcherID leads to less ambiguous and more reliable author information, but it requires engagement of the authors. In order to minimize the effort needed to integrate with ORCID, users can link the ResearcherID platform with their ORCID account121212http://wokinfo.com/researcherid/integration to send their publication list from ResearcherID to ORCID and vice versa. ORCID is focussed solely on providing persistent identifiers for researchers. The ORCID technology is open source and the web platform can be integrated into other services using various APIs131313https://orcid.org/organizations/integrators/API. This openness might be crucial to encourage researchers and service providers to adopt ORCID.

We showed, that at the time of writing, the majority of researchers do not use ORCID or ResearcherID. The steadily growing number of ORCID users indicates that this might change in the future, but as long as this is the case it is necessary to elaborate automated author disambiguation technologies for resilient bibliometrics and increase their accuracy Momeni and Mayr (2016); Swijghuisen Reigersberg (2015).

6 Acknowlegdement

This work was partly funded by BMBF (Federal Ministry of Education and Research, Germany) under grant number 01PQ13001. We thank your colleagues at the Competence Centre for Bibliometrics and Leibniz Institute for Information Infrastructure (FIZ Karlsruhe) for providing access and assistance.

References

7 Appendix

7.1 Author identifiers in WoS subject areas

Subject area Scopus rid orcid
Biochemistry & Molecular Biology 1,256,720 61,655 24,721
Materials Science, Multidisciplinary 983,555 82,838 32,940
Physics, Applied 822,106 65,837 25,854
Chemistry, Physical 798,542 76,455 30,708
Multidisciplinary Sciences 820,757 42,387 19,002
Chemistry, Multidisciplinary 747,621 64,639 25,382
Oncology 792,495 17,247 6,174
Neurosciences 699,094 29,141 12,007
Pharmacology & Pharmacy 685,833 22,422 8,983
Cell Biology 664,492 27,041 10,428
Surgery 652,405 9,574 3,340
Engineering, Electrical & Electronic 586,457 29,394 12,475
Environmental Sciences 548,327 39,123 17,694
Biotechnology & Applied Microbiology 555,379 27,943 11,852
Immunology 569,124 16,026 5,939
Genetics & Heredity 541,310 25,625 10,575
Physics, Condensed Matter 498,070 52,875 21,306
Nanoscience & Nanotechnology 467,866 46,393 18,271
Clinical Neurology 499,098 13,918 5,481
Microbiology 444,834 18,981 7,808
Physics, Multidisciplinary 378,029 30,250 13,166
Medicine, Research & Experimental 403,176 11,204 4,405
Public, Environmental & Occupational Health 401,694 11,766 5,040
Endocrinology & Metabolism 400,239 12,950 5,134
Chemistry, Organic 381,821 20,184 7,981
Radiology, Nuclear Medicine & Medical Imaging 391,466 11,826 4,814
Chemistry, Analytical 366,278 22,824 9,627
Cardiac & Cardiovascular System 388,487 7,291 2,753
Biochemical Research Methods 358,469 21,718 9,318
Engineering, Chemical 356,641 21,956 9,406
Plant Sciences 336,511 20,052 8,535
Hematology 339,350 8,611 3,164
Medicine, General & Internal 339,698 6,950 2,721
Biophysics 307,776 18,170 7,460
Infectious Diseases 312,904 7,732 3,002
Food Science & Technology 302,714 13,962 6,477
Pediatrics 313,091 5,361 1,931
Energy & Fuels 290,779 17,550 7,686
Chemistry, Medicinal 298,768 10,729 4,246
Biology 288,089 17,706 7,538
Instruments & Instrumentation 288,854 16,401 6,966
Geosciences, Multidisciplinary 277,734 23,088 10,176
Optics 277,831 19,587 8,219
Psychiatry 287,043 10,828 4,674
Polymer Science 273,400 20,009 7,798
Physics, Atomic, Molecular & Chemical 251,968 29,009 12,346
Gastroenterology & Hepatology 284,031 5,214 1,863
Astronomy & Astrophysics 263,826 12,110 5,284
Ecology 244,281 25,280 11,310
Peripheral Vascular Diseases 270,018 6,621 2,456
Chemistry, Applied 257,403 13,591 5,969
Physiology 234,179 9,889 3,849
Toxicology 233,588 9,398 3,873
Chemistry, Inorganic & Nuclear 216,507 16,162 6,648
Obstetrics & Gynecology 224,383 4,221 1,634
Electrochemistry 202,755 15,001 6,253
Urology & Nephrology 217,652 3,986 1,470
Nutrition & Dietetics 210,908 8,264 3,596
Physics, Particles & Fields 209,743 8,488 3,525
Engineering, Biomedical 205,175 11,495 4,725
Mechanics 190,388 14,404 6,351
Engineering, Environmental 190,089 13,884 6,356
Metallurgy & Metallurgical Engineering 192,307 12,245 5,296
Spectroscopy 192,772 11,384 4,676
Respiratory System 201,044 4,160 1,484
Virology 196,141 6,103 2,410
Pathology 194,008 4,604 1,689
Engineering, Mechanical 184,360 10,114 4,295
Veterinary Sciences 188,316 6,598 2,710
Meteorology & Atmospheric Sciences 170,201 16,887 7,570
Nuclear Science & Technology 183,571 7,730 3,157
Mathematics, Applied 174,821 10,513 4,790
Computer Science, Interdisciplinary Applications 171,857 11,701 5,684
Marine & Freshwater Biology 162,891 13,465 5,954
Water Resources 164,469 11,581 5,253
Orthopedics 163,871 2,982 1,191
Engineering, Civil 154,356 9,313 4,348
Crystallography 148,793 10,613 4,363
Geochemistry & Geophysics 141,171 12,737 5,482
Transplantation 149,401 3,088 1,062
Health Care Sciences & Services 143,766 3,714 1,616
Materials Science, Coatings & Films 134,968 9,339 3,845
Physics, Fluids & Plasmas 126,520 10,891 4,735
Computer Science, Information Systems 133,149 5,639 2,669
Dentistry, Oral Surgery & Medicine 131,624 4,108 1,345
Ophthalmology 132,767 2,897 1,135
Telecommunications 127,165 5,334 2,274
Dermatology 130,731 2,317 897
Zoology 122,289 8,191 3,349
Agronomy 123,303 6,429 2,904
Materials Science, Biomaterials 120,169 7,821 3,099

Computer Science, Artificial Intelligence

118,095 6,937 3,454
Sport Sciences 119,920 4,270 1,791
Behavioral Sciences 115,975 6,884 2,975
Parasitiology 117,331 5,289 2,111
Physics, Mathematical 109,077 10,658 4,918
Critical Care Medicine 120,190 2,440 928
Economics 115,749 4,467 2,140
Mathematics 113,815 4,982 2,231
Physics, Nuclear 107,096 5,943 2,564
Rheumatology 111,076 2,555 1,018
Engineering, Multidisciplinary 104,843 5,960 2,741
Psychology 105,450 5,376 2,348
Evolutionary Biology 98,061 10,339 4,580
Psychology, Clinical 105,390 3,641 1,528
Rehabilitation 105,498 3,078 1,269
Developmental Biology 103,322 4,509 1,719
Geriatrics & Gerontology 103,823 3,751 1,520
Reproductive Biology 103,928 3,514 1,403
Thermodynamics 98,378 5,671 2,557
Mathematical & Computational Biology 96,268 6,745 3,242
Oceanography 91,393 8,484 3,976
Mathematics, Interdisciplinary Applications 93,318 6,649 3,083
Agriculture, Multidisciplinary 90,952 5,362 2,534
Computer Science, Software Engineering 91,754 4,207 1,985
Agriculture, Dairy & Animal Science 91,979 3,448 1,565
Operations Research & Management Science 87,893 5,125 2,440
Otorhinolaryngology 90,801 1,428 457
Psychology, Multidisciplinary 86,782 3,081 1,433
Psychology, Experimental 80,966 4,868 2,179
Computer Science, Theory & Methods 81,640 3,980 1,928
Anesthesiology 83,430 1,482 561
Automation & Control Systems 77,679 4,673 2,197
Geography, Physical 73,991 6,662 3,069
Fisheries 75,959 4,590 2,014
Materials Science, Ceramics 73,053 4,825 2,083
Nursing 77,911 1,378 666
Engineering, Manufacturing 72,987 3,530 1,588
Medical Laboratory Technology 74,890 1,628 604
Health Policy & Services 74,082 1,821 828

Statistics & Probability

70,142 3,527 1,598
Management 70,097 3,070 1,461
Soil Science 66,746 5,322 2,320
Entomology 65,502 3,811 1,537
Psychology, Developmental 66,871 2,163 857
Tropical Medicine 66,407 1,977 800
Acoustics 64,185 3,204 1,403
Neuroimaging 61,651 3,452 1,533
Education & Educational Research 63,173 1,557 711
Emergency Medicine 64,179 823 349
Biodiversity Conservation 56,081 5,941 2,614
Forestry 56,561 4,666 2,081
Integrative & Complementary Medicine 61,011 1,402 614
Computer Science, Hardware & Architecture 59,114 2,255 980
Environmental Studies 57,358 3,282 1,683
CELL & TISSUE ENGINEERING 58,880 2,407 906
Construction & Building Technology 56,236 2,872 1,377
Agricultural Engineering 54,673 3,241 1,472
Engineering, Industrial 54,623 2,822 1,319
Substance Abuse 53,831 1,544 709
Allergy 53,964 1,331 486
Gerontology 49,343 1,612 653
Remote Sensing 45,947 3,537 1,744
Medical Informatics 48,041 1,797 783
Business 45,039 1,731 766
Materials Science, Composites 42,725 2,807 1,233
Horticulture 43,288 2,049 927
Imaging Science & Photographic Technology 40,866 3,022 1,429
Psychology, Social 42,662 1,673 691
Mineralogy 39,911 3,224 1,327
Education, Scientific Disciplines 41,820 1,181 594
Anatomy & Morphology 39,503 1,748 648
Social Sciences, Interdisciplinary 39,062 1,293 625
Social Sciences, Biomedical 39,252 1,078 465
Psychology, Applied 37,772 1,381 551
Limnology 33,200 3,217 1,399
Mining & Mineral Processing 34,398 1,824 787
Mycology 33,552 1,825 764
Geology 31,450 2,500 1,004
Medicine, Legal 32,472 869 400
Information Science & Library Science 31,160 1,663 894
Materials Science, Characterization, Testing 30,062 1,767 808
Paleontology 28,681 2,205 934
Engineering, Aerospace 30,096 1,189 483
Transportation Science & Technology 29,061 1,476 645
Engineering, Geological 28,542 1,693 772
Business, Finance 29,634 883 333
Geography 26,731 1,597 763
Linguistics 26,786 853 370
Microscopy 24,798 1,979 838
Sociology 25,846 913 397
Anthropology 24,749 1,263 626
Family Studies 25,566 519 218
Psychology, Biological 23,561 1,399 660
AUDIOLOGY & SPEECH-LANGUAGE PATHOLOGY 23,155 1,025 418
Psychology, Educational 23,105 639 277
Materials Science, Textiles 21,540 1,017 470
Robotics 21,017 1,111 509
Political Science 20,684 650 273
Planning & Development 20,237 819 407
Social Work 20,765 403 180
Transportation 19,266 1,032 497
Social Sciences, Mathematical Methods 18,818 858 391
Ergonomics 18,782 837 401
Communication 18,702 543 234
Education, Special 18,090 459 221
Archaeology 17,347 849 417
PRIMARY HEALTH CARE 17,766 502 251
Criminology & Penology 16,556 319 136
Urban Studies 15,062 710 332
Computer Science, Cybernetics 14,705 768 382
Engineering, Petroleum 14,808 395 177
Women’s Studies 14,437 253 102
Engineering, Ocean 13,058 871 393
Hospitality, Leisure, Sport & Tourism 13,143 494 256
International Relations 12,663 385 171
Ornithology 11,503 1,011 427
Ethics 12,496 309 127
Andrology 11,678 289 113
Social Issues 11,581 310 126
Language & Linguistics Theory 11,469 252 116
Materials Science, Paper & Wood 10,562 627 279
Public Administration 10,454 355 168
Law 10,358 176 73
Psychology, Mathematical 7,344 401 182
History & Philosophy of Science 6,958 206 98
Medical Ethics 7,016 174 71
Demography 6,361 167 77
Engineering, Marine 6,202 259 127
Agricultural Economics & Policy 5,954 267 143
Industrial Relations & Labor 5,739 152 72
History 4,887 69 41
Area Studies 4,222 84 40
Religion 4,239 58 25
LOGIC 3,715 209 117
Ethnic Studies 3,918 80 29
Philosophy 3,715 64 39
Art 3,190 162 84
History of Social Sciences 3,086 92 52
Humanities, Multidisciplinary 3,043 52 31
Psychology, Psychoanalysis 2,501 52 21
CULTURAL STUDIES 2,361 34 16
Music 1,998 47 20
Architecture 1,843 77 48
Literature 1,567 22 11
Film, Radio, Television 795 20 8
Asian Studies 704 5 1
Theater 506 2 0
Medieval & Renaissance Studies 253 3 1
Literary Reviews 160 0 0
Dance 128 0 0
Literature, Romance 122 1 1
Literary Theory & Criticism 91 0 0
Folklore 87 2 1
Classics 85 0 0
Literature, German, Dutch, Scandinavian 67 0 0
Literature, British Isles 62 0 0
Literature, American 53 0 0
Literature, African, Australian, Canadian 27 0 0
Poetry 5 0 0