Searching for Science: a comparison of Web of Science and Scopus Linda Humphreys University of Bath

1. Searching for Science: a comparison of Web of Science and Scopus Linda Humphreys University of Bath

2. Introduction Content Currency Author Searching Keyword Searching Citation Searching

3. Content WoS: 8,700 journals All subject areas Conferences in ISI Proceedings Patents in Derwent Inovations Index Scopus: 14,000 journals Sciences and Social Sciences Conferences included Patents searched separately Claims: �Scopus is the most comprehensive scientific, medical, technical and social science point of access containing all relevant literature� (Scopus web page) WoK �Excellence not excess� Quantity easier to measure than quality! Number of journals DOES mean current titles. There are many more appearing in both databases. Note Scopus does not cover Arts and Humanities. Both index editorials, book reviews and letters from journals (?comprehensive) Both include some book series (ISI about 300) NB Not quite comparing like with like as Scopus includes conferences whereas in WoK they are a separate product Scopus includes Scirus results: web sites, theses and eprints: the latter two are lost in the other web resultsClaims: �Scopus is the most comprehensive scientific, medical, technical and social science point of access containing all relevant literature� (Scopus web page) WoK �Excellence not excess� Quantity easier to measure than quality! Number of journals DOES mean current titles. There are many more appearing in both databases. Note Scopus does not cover Arts and Humanities. Both index editorials, book reviews and letters from journals (?comprehensive) Both include some book series (ISI about 300) NB Not quite comparing like with like as Scopus includes conferences whereas in WoK they are a separate product Scopus includes Scirus results: web sites, theses and eprints: the latter two are lost in the other web results

4. Content: WoS SCI 1900- (abstracts from 1991 and keywords from 1991) SSCI 1956- (abstracts from 1992 and keywords from 1991) AHCI 1975- (abstracts from 2000 and keywords from 1991) Content: We want databases to be both comprehensive and relevant to our subject area. To make sense of comparative test results, we need to understand how the databases are structured. WoS was designed from the beginning as a citation database. Author abstracts and keywords were added later, to improve subject searching capabilities. Because the backfiles are available as separate purchases, we don�t all have access back to 1900! Content: We want databases to be both comprehensive and relevant to our subject area. To make sense of comparative test results, we need to understand how the databases are structured. WoS was designed from the beginning as a citation database. Author abstracts and keywords were added later, to improve subject searching capabilities. Because the backfiles are available as separate purchases, we don�t all have access back to 1900!

5. Content: Scopus Publisher-submitted records 1996- PubMed records 1966- Content from other Elsevier databases*: Embase 1970- - Fluidex 1974- Compendex 1970- - Geobase 1980- World Textile Index 1970- Biobase 1994- *Source: Deis and Goodman, 2005 Scopus is not primarily designed as a citation index, but does include citations to articles from 1996 -. Aims for comprehensive coverage from 1996 to date. (Hence this appears as a start date for testing) Current records are submitted by various publishers (over 4,000), inc Elsevier themselves. Have included complete set of PubMed records from 1966 Records from other Elsevier databases are also included and help to extend coverage back in time. �abstracts go back to 1966� but I don�t know what percentage of records have them. Obviously they won�t be present for editorials, letters, etc. Scopus is not primarily designed as a citation index, but does include citations to articles from 1996 -. Aims for comprehensive coverage from 1996 to date. (Hence this appears as a start date for testing) Current records are submitted by various publishers (over 4,000), inc Elsevier themselves. Have included complete set of PubMed records from 1966 Records from other Elsevier databases are also included and help to extend coverage back in time. �abstracts go back to 1966� but I don�t know what percentage of records have them. Obviously they won�t be present for editorials, letters, etc.

6. Content 5 high-impact factor science journals: Nature Science British Medical Journal Lancet Tetrahedron Letters Journal title search 1976-85, WoS finds more for all titles. Maybe expected for Nature, Science? But BMJ and Lancet are indexed by PubMEd and Embase so why aren�t they finding more? Tet Letters is an Elsevier journal! I would have expected Elsevier to have loaded backdata for their own titles. 5 high-impact factor science journals: Nature Science British Medical Journal Lancet Tetrahedron Letters Journal title search 1976-85, WoS finds more for all titles. Maybe expected for Nature, Science? But BMJ and Lancet are indexed by PubMEd and Embase so why aren�t they finding more? Tet Letters is an Elsevier journal! I would have expected Elsevier to have loaded backdata for their own titles.

7. Content Likewise, although TL is doing somewhat better.Likewise, although TL is doing somewhat better.

8. Content 1996-2005 still shows WoS finding more hits from all 5 journals You would expect a very small variation due to difference in currency Both claim to include letters, editorials, book reviews, although this could also account for some differences. The difference is between 1k and 7k records, or WoS finding approx 5-20% more items, so in my opinion this indicates gaps in Scopus coverage This is the most serious area of concern that I have found. 1996-2005 still shows WoS finding more hits from all 5 journals You would expect a very small variation due to difference in currency Both claim to include letters, editorials, book reviews, although this could also account for some differences. The difference is between 1k and 7k records, or WoS finding approx 5-20% more items, so in my opinion this indicates gaps in Scopus coverage This is the most serious area of concern that I have found.

9. Currency WoS is updated weekly, Scopus daily But what is really important is how up to date with journal issues they are � we need the latest information. Selected 10 science journals Comparison of: Latest available issue on publisher�s web site Latest issue on WoS Latest issue on Scopus BOTH are pretty good here, especially considering that these are weekly journals. TL is an Elsevier title�. WoS is updated weekly, Scopus daily But what is really important is how up to date with journal issues they are � we need the latest information. Selected 10 science journals Comparison of: Latest available issue on publisher�s web site Latest issue on WoS Latest issue on Scopus BOTH are pretty good here, especially considering that these are weekly journals. TL is an Elsevier title�.

10. Currency Again for these titles, currency is good in both databases (JACS = Journal of the American Chemical Society and NEJM = New England Journal of Medicine) Overall, Web of Science has better currency for 6 out of 10 of the selected titles. Scopus better for 3: (inc Elsevier title). One equal. NB NEJM is on Highwire, the rest on publisher�s own site NB Problem with Pharm J on WoS � only 5 articles from 2005, so this is patchy too! Again for these titles, currency is good in both databases (JACS = Journal of the American Chemical Society and NEJM = New England Journal of Medicine) Overall, Web of Science has better currency for 6 out of 10 of the selected titles. Scopus better for 3: (inc Elsevier title). One equal. NB NEJM is on Highwire, the rest on publisher�s own site NB Problem with Pharm J on WoS � only 5 articles from 2005, so this is patchy too!

11. My searches so far were on journal title� Screen shot: Scopus search for journal title = science Journal title search in Scopus is annoying. You have to use the refine tool to narrow it down to the title you want, as it does a �word in title� not an �exact title� search. E.g. this is finding PNAS BMJ indexed under BMJ and under British Medical Journal due to different record sources: need to standardise. WoS is better for journal title searchesMy searches so far were on journal title� Screen shot: Scopus search for journal title = science Journal title search in Scopus is annoying. You have to use the refine tool to narrow it down to the title you want, as it does a �word in title� not an �exact title� search. E.g. this is finding PNAS BMJ indexed under BMJ and under British Medical Journal due to different record sources: need to standardise. WoS is better for journal title searches

12. Author searching Both databases currently index all authors and all affiliations given in the source. May not be consistent for entire databases but certainly since 1996 for Scopus and last 20 yrs for WoK Selected authors from three University of Bath Departments: Pharmacy and Pharmacology (5) Chemistry (6) Physics (6) Time period: All years available For Pharmacy, WoS more for 4 out of 5 For all Chemistry authors, WoS found more hits For Physics, WoS more for 5 out of 6 Both databases currently index all authors and all affiliations given in the source. May not be consistent for entire databases but certainly since 1996 for Scopus and last 20 yrs for WoK Selected authors from three University of Bath Departments: Pharmacy and Pharmacology (5) Chemistry (6) Physics (6) Time period: All years available For Pharmacy, WoS more for 4 out of 5 For all Chemistry authors, WoS found more hits For Physics, WoS more for 5 out of 6

13. Author searching Same authors, 1996-2005 Pharmacy � 4 out of 5 more on WoS Chemistry � WoS more for all Physics � 4 out of 5 more hits on Scopus this time NB Some of these could be from conferences, which are not included in my WoS searches, so not comparing exactly like with like Same authors, 1996-2005 Pharmacy � 4 out of 5 more on WoS Chemistry � WoS more for all Physics � 4 out of 5 more hits on Scopus this time NB Some of these could be from conferences, which are not included in my WoS searches, so not comparing exactly like with like

14. Author searching: Certain authors are impossible to find using either database (e.g. Wang, Smith) Usual solution: author + affiliation Affiliation is not always present Affiliation is not linked to author WoS does have an authority file for affiliation One of my original author choices was Wang� even with initials there was no way to limit to the correct author (on either database). Problems with Smiths and Jones� well known. Usually we add affiliation to identify the correct author. But affiliation is not always present in the source article; Author not linked to affiliation so if you search for Jones and Bath you may find an article by Smith and Jones where Smith is at Bath and Jones is at Bristol ISI do have an authority file of the institution name and address and correct any variations e.g. Bath University will be changed to Univ Bath They also add complete addresses such as dept name, street address and postcode. May not be perfectly implemented for the whole WoS database (esp where Institutions change name?) but a big step in the right direction. Both databases need to improve author searching. Need to link authors to affiliation. Since a particular author normally collaborates with similar co-authors, could you use that to write a program to identify them? One of my original author choices was Wang� even with initials there was no way to limit to the correct author (on either database). Problems with Smiths and Jones� well known. Usually we add affiliation to identify the correct author. But affiliation is not always present in the source article; Author not linked to affiliation so if you search for Jones and Bath you may find an article by Smith and Jones where Smith is at Bath and Jones is at Bristol ISI do have an authority file of the institution name and address and correct any variations e.g. Bath University will be changed to Univ Bath They also add complete addresses such as dept name, street address and postcode. May not be perfectly implemented for the whole WoS database (esp where Institutions change name?) but a big step in the right direction. Both databases need to improve author searching. Need to link authors to affiliation. Since a particular author normally collaborates with similar co-authors, could you use that to write a program to identify them?

15. Scopus: where available the full author names are included, hence the wording we see on the search screen. (I think this is in ADDITION to indexing with initials, but not certain) In author search, you are asked to input either first name or initials But if you do enter first name, you miss most of the hits! Here there are 5 for Michael J Willis, none for Michael C, the one I was looking for Scopus: where available the full author names are included, hence the wording we see on the search screen. (I think this is in ADDITION to indexing with initials, but not certain) In author search, you are asked to input either first name or initials But if you do enter first name, you miss most of the hits! Here there are 5 for Michael J Willis, none for Michael C, the one I was looking for

16. there are really 50, but listed under his *Initials* Enhancement request: remove the �or first name� from this screen! Also, there is no way to combine an author search with affiliation (or year) from the author search screen�. there are really 50, but listed under his *Initials* Enhancement request: remove the �or first name� from this screen! Also, there is no way to combine an author search with affiliation (or year) from the author search screen�.

17. If you want to combine an author name with a year range or affilliation, have to use Basic or Advanced search, not author search� and then .. Inverted initials in basic or advanced search: Willis MC or Willis CM? In WoS, much better�. from the general search screen where you can enter author or corporate author and affiliation and publication date. If you want to combine an author name with a year range or affilliation, have to use Basic or Advanced search, not author search� and then .. Inverted initials in basic or advanced search: Willis MC or Willis CM? In WoS, much better�. from the general search screen where you can enter author or corporate author and affiliation and publication date.

18. Keyword searching Neither database has a thesaurus WoS has �keywords plus� Scopus adds author keywords plus some indexing terms from other Elsevier databases and PubMed Scopus also adds CAS numbers from Embase and PubMed In both cases, searching title and abstracts, where the latter are available. In WoS, 1991 (SCI), 1992 (SSCI) and 2000 (AHCI) Scopus claims 1966. Need to consider what additional indexing is available. WoS started to add keywords in 1991. Before that date you would basically only be searching titles. WoS has two types of keywords: author keywords and �keywords plus�, which are machine-generated. Look at the titles of the CITED REFS and pick out any terms that appear in two or more of them. Hence there won�t be any keywords plus for items that have not been cited. No controlled vocabulary, i.e.. there will be variations in spellings and endings of words. Scopus claim �81% of content is indexed with controlled vocabularies� but doesn�t use a thesaurus, even though some of its records come from databases that have one e.g. Embase. In my opinion, neither database has the quality of indexing of the more subject-specific databases e.g. SciFinder, PubMed, Embase In both cases, searching title and abstracts, where the latter are available. In WoS, 1991 (SCI), 1992 (SSCI) and 2000 (AHCI) Scopus claims 1966. Need to consider what additional indexing is available. WoS started to add keywords in 1991. Before that date you would basically only be searching titles. WoS has two types of keywords: author keywords and �keywords plus�, which are machine-generated. Look at the titles of the CITED REFS and pick out any terms that appear in two or more of them. Hence there won�t be any keywords plus for items that have not been cited. No controlled vocabulary, i.e.. there will be variations in spellings and endings of words. Scopus claim �81% of content is indexed with controlled vocabularies� but doesn�t use a thesaurus, even though some of its records come from databases that have one e.g. Embase. In my opinion, neither database has the quality of indexing of the more subject-specific databases e.g. SciFinder, PubMed, Embase

19. Example article � looked at indexing in WoS and Scopus This is the WoS record, keywords Example article � looked at indexing in WoS and Scopus This is the WoS record, keywords

20. This is much better indexed than the WoS record, you can see indexing terms from Embase and Medline (but NOT all terms, and not structured) Interesting to see the added CAS numbers here� very handy for pharmacy and pharmacology. But because they come from PubMed and Embase, they won�t be available for most compounds of interest to chemists. This is much better indexed than the WoS record, you can see indexing terms from Embase and Medline (but NOT all terms, and not structured) Interesting to see the added CAS numbers here� very handy for pharmacy and pharmacology. But because they come from PubMed and Embase, they won�t be available for most compounds of interest to chemists.

21. Another example� This is from PubMed record (MH = Mesh terms) Look at record for this on Scopus, there are NO index terms�.? Why should this fall in the 19% of records without indexing, if the terms were available via the PubMed data?Another example� This is from PubMed record (MH = Mesh terms) Look at record for this on Scopus, there are NO index terms�.? Why should this fall in the 19% of records without indexing, if the terms were available via the PubMed data?

22. Keyword searching Differences in interpretation of search: e.g. Needle exchange WoS: Phrase search �needle exchange� Scopus: needle AND exchange Users familiar with WoK will assume that Scopus works in the same way. Scopus need to use �� (not intuitive, but there is an example on the screen) Also it is fairly clear from your Scopus results that the words have not been searched as a phraseUsers familiar with WoK will assume that Scopus works in the same way. Scopus need to use �� (not intuitive, but there is an example on the screen) Also it is fairly clear from your Scopus results that the words have not been searched as a phrase

23. Keyword searching Scopus: automatic truncation �entering criterion will locate criteria and criterion� Horse � 38,667 hits Horses � 38,667 hits Behaviour � 324,286 hits Behavior � 903,878 hits Behav* - 1,321,763 hits Another feature of Scopus is automatic truncation. from Scopus web page: �Using the singular word form will retrieve the singular, plural and possessive forms of most words� Checked criterion and it really did work!! Checked Gene and it didn�t find general! Didn�t find genetic either. Doesn�t take account of different spellings, and the word �behaviour� wasn�t automatically truncated. This is a really useful feature but as a librarian, I�d like more info please!Another feature of Scopus is automatic truncation. from Scopus web page: �Using the singular word form will retrieve the singular, plural and possessive forms of most words� Checked criterion and it really did work!! Checked Gene and it didn�t find general! Didn�t find genetic either. Doesn�t take account of different spellings, and the word �behaviour� wasn�t automatically truncated. This is a really useful feature but as a librarian, I�d like more info please!

24. Citation searching Selected 5 journal article references from University of Bath web pages for research in Chemistry, Pharmacy, Physics Number of times cited? More or less at random but 2 Physics ones distorted by my selection� Again, you are assessing the content of the database: some citations will be in conference papers, which in Scopus are included and WoS not. For Chemistry, WoS found more for 3 articles and Scopus for 1 (1 equal) In Pharmacy, the reverse. Scopus found more for 3, WoS 1, 1 equal Physics Scopus found more for 3, WoS for 1, 5th wasn�t in Scopus database So inconclusive for these RECENT papers, but�.. Selected 5 journal article references from University of Bath web pages for research in Chemistry, Pharmacy, Physics Number of times cited? More or less at random but 2 Physics ones distorted by my selection� Again, you are assessing the content of the database: some citations will be in conference papers, which in Scopus are included and WoS not. For Chemistry, WoS found more for 3 articles and Scopus for 1 (1 equal) In Pharmacy, the reverse. Scopus found more for 3, WoS 1, 1 equal Physics Scopus found more for 3, WoS for 1, 5th wasn�t in Scopus database So inconclusive for these RECENT papers, but�..

25. Citation searching King, M.C. and Wilson, A.C. 1975. Evolution at two levels in humans and chimpanzees. Science: 188, 107-116. WoS: 782 citations (inc. 10 mis-citations) Scopus: 232 citations Tried several more older articles, with similar results. Big difference for older articles, as you would expect, as Scopus is adding citations from 1996. This indicates that a *long period* of comprehensive coverage is important for citation searching, which we have got in WoS but not in Scopus. Tried several more older articles, with similar results. Big difference for older articles, as you would expect, as Scopus is adding citations from 1996. This indicates that a *long period* of comprehensive coverage is important for citation searching, which we have got in WoS but not in Scopus.

26. Cited ref search in WoS� WoS only index the first author of a cited work, but where there is a full record for the cited work in the WoK database all of the authors are searchable. But you can�t easily use it to search for all citations to all of an author�s work.. Would need to know all of the first authors, for any items not in the WoS database. On the positive side, WoS lookup screen enables you to spot incorrect citations of a work, or where a page within an article has been cited. Cited ref search in WoS� WoS only index the first author of a cited work, but where there is a full record for the cited work in the WoK database all of the authors are searchable. But you can�t easily use it to search for all citations to all of an author�s work.. Would need to know all of the first authors, for any items not in the WoS database. On the positive side, WoS lookup screen enables you to spot incorrect citations of a work, or where a page within an article has been cited.

27. Scopus - no cited reference search screen, just find the article in the database and automatically have the list of �cited by�. It is easier, but�. What happens to mis-citations and citations to pages within an article? Useful to have conferences included in the same database. Would be even better if eprints and theses were included too. Q: how do you find citations to items that aren�t in the Scopus database�.?Scopus - no cited reference search screen, just find the article in the database and automatically have the list of �cited by�. It is easier, but�. What happens to mis-citations and citations to pages within an article? Useful to have conferences included in the same database. Would be even better if eprints and theses were included too. Q: how do you find citations to items that aren�t in the Scopus database�.?

28. A: Have to use �advanced search��..not so easy. For this example, WoS found 208 (plus a few incorrect) With above search, Scopus found 2, and on further investigation neither were citing the correct article: Scopus doesn�t just return a list of records that have cited the paper you want, it just looks at the terms entered in isolation� so you may get an item with 3 references, one by Adams, one from Nature and one from 1970! Also it is searching the author�s initials separately, as I got: Adams SM and Hosie MJ! A strange decision on Elsevier�s part! Of course this example is from an old paper, Scopus works much better with more recent ones. A: Have to use �advanced search��..not so easy. For this example, WoS found 208 (plus a few incorrect) With above search, Scopus found 2, and on further investigation neither were citing the correct article: Scopus doesn�t just return a list of records that have cited the paper you want, it just looks at the terms entered in isolation� so you may get an item with 3 references, one by Adams, one from Nature and one from 1970! Also it is searching the author�s initials separately, as I got: Adams SM and Hosie MJ! A strange decision on Elsevier�s part! Of course this example is from an old paper, Scopus works much better with more recent ones.

29. Summary Scopus needs to fill in gaps in coverage and provide more information on coverage Both databases need to improve author searching Scopus is better for keyword searching WoS is better for citation searching

30. Conclusion �Don�t cancel WoK, buy Scopus if you can� Deis, L.F. and Goodman, D. 2005. Web of Science (2004 version) and Scopus. The Charleston Advisor. vol.6, no.3. http://charlestonco.com/comp.cfm?id=43 Agree with the conclusion of Deis and Goodman, Charleston Adviser�Agree with the conclusion of Deis and Goodman, Charleston Adviser�