Data source |
Advantages |
Disadvantages |
Crossref |
- No need for a subscription key
- Usually provides cleaner and smaller number of irrelevant results than Google Scholar and Microsoft Academic
- Good data source for keyword searches and journal searches by ISSN
- Search speed fast
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- Reports fewer citations than Google Scholar and Open, because it has more limited coverage
- The use of NOT or AND in keyword searches results is ignored; Crossref reverts to OR searches
- Author search is problematic as it is very difficult to disambiguate authors
- Year of publication is year of online-first, which may be different from year of print publication
- Provides abstracts for some results only
|
Google Scholar (GS) |
- No need for a subscription key
- "Forgiving" search syntax
- Usually provides the largest number of publications and citations
- Search speed medium for single search with limited number of results
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- Usually provides a larger number of irrelevant results than other data sources
- Author disambiguation more difficult than GSP, MA and WoS
- Because of necessary search rate limitation, speed slows down considerably when doing multiple searches in quick succession or running searches with many results
- Year of publication can be year of online first, for up to a year of print publication
- Provides the first few lines of abstracts only
|
Google Scholar Profile (GSP) |
- No need for a subscription key
- Most "forgiving" search syntax
- Very quick search, 1-3 seconds for most authors
- Manual curation by the academic usually means cleaner results than GS
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- Only available if academic in question has set up a profile
- Can contain "dirty data" if academic has not curated their profile
- Can be consciously manipulated by unscrupulous academics by adding papers not written by the academic themselves
- Does not provide abstracts
|
Microsoft Academic (MA) |
- Usually provides a smaller number of irrelevant results than GS
- Search speed very fast for searches with less than 200 results, but fast even for repeated searches and searches with many results
- Usually provides cleaner results than GSP as not all user curate their GSP
- Seems to provide best automated author disambiguation
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- Service was discontinued in December 2021
- More restrictive search syntax
- The use of NOT in keyword searches results in an error message
- Because MA favours semantic over lexical searches, it results in an error message if you include stop words such as "the", "a", "from", but also common academic words such as study and method.
- Year of publication is usually year of online first, not year of print publication
- Requires a (free) Microsoft subscription key
|
OpenAlex |
- No need for a subscription key
- Search speed fast even for repeated searches and searches with many results
- Coverage second only to Google Scholar
- Provides full abstracts for all results
|
- Author search requires ORCID of OA ID. Cannot conduct an author search by name
- Journal search requires OA ID. Cannot conduct a journal search by name
- Affiliation search requires OA ID. Cannot search by university name
|
PubMed |
- No need for subscription key
- Provides a maximum of 1000 results for journal and keyword searches; higher maximum with free NCBI API key
- Includes abstracts in results
|
- Specialized data source for biomedical subjects only
- for unknown reasons some author/affiliation searches and some title/keyword searches are restricted to either 199 or 398 results
- Does NOT include citations; hence citation metrics cannot be calculated
|
Scopus |
- Provides cleaner and smaller number of irrelevant results than Google Scholar and Microsoft Academic
- Typically reports more citations than Web of Science
- Very good data source for keyword searches and journal searches by ISSN
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- Requires a free API key from Elsevier for basic results
- Full results require (non-free) subscription
- Search speed slow, but still acceptable
- Typically reports fewer citations than Google Scholar and Microsoft Academic, because it includes fewer journals in some fields and has a limited coverage of books, book chapters and conference papers
- Does not provide abstracts
|
Semantic Scholar
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- Access courtesy of S2. You do not need a subscription key.
- Useful source for keyword searches.
- Search speed fast even for repeated searches and searches with many results
- Second only to GS(P) in terms of coverage and citation rates
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- Due to current structure of its API, you are only able to do keyword searches
- Keywords are matched anywhere in the document. No ability to restrict searches to the title only
- Does not provide full bibliographic details, only author title and year, no publication source, or other details
- Does not provide abstracts
|
Web of Science |
- Provides cleaner and smaller number of irrelevant results than Google Scholar and Microsoft Academic
- Search speed very fast for nearly any kind of searches
- Allows wildcards (e.g. global*) for easier searches
- Very good data source for keyword searches and journal searches by ISSN
- Provides full abstracts for all results
|
- Requires (non-free) subscription
- Typically reports fewer citations than all other sources because it includes fewer journals in many fields (esp. Social Sciences and Humanities) and has a very limited coverage of books, book chapters and conference papers.
- Typically is last data source to include recent publications as it doesn’t include “in press” papers.
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