citation index is built on the fact that citations in science serve as linkages between similar research items, and lead to matching or related scientific literature, such as
conference proceedings, abstracts, etc. In addition, literature that shows the greatest impact in a particular field, or more than one discipline, can be easily located through a citation index. For example, a paper's influence can be determined by linking to all the papers that have cited it. In this way, current trends, patterns, and emerging fields of research can be assessed.
Eugene Garfield, the "father of citation indexing of academic literature", who launched the
Science Citation Index, which in turn led to the Web of Science, wrote:
Citations are the formal, explicit linkages between papers that have particular points in common. A citation index is built around these linkages. It lists publications that have been cited and identifies the sources of the citations. Anyone conducting a literature search can find from one to dozens of additional papers on a subject just by knowing one that has been cited. And every paper that is found provides a list of new citations with which to continue the search.
The simplicity of citation indexing is one of its main strengths.
Web of Science is described as a unifying research tool that enables the user to acquire, analyze, and disseminate database information in a timely manner. This is accomplished because of the creation of a common vocabulary, called
ontology, for varied search terms and varied data. Moreover, search terms generate related information across categories.
Acceptable content for Web of Science is determined by an evaluation and selection process based on the following criteria: impact, influence, timeliness,
peer review, and geographic representation.
Web of Science employs various search and analysis capabilities. First, citation indexing is employed, which is enhanced by the capability to search for results across disciplines. The influence, impact, history, and
methodology of an idea can be followed from its first instance, notice, or referral to the present day. This technology points to a deficiency with the
keyword-only method of searching.
Second, subtle trends and patterns relevant to the literature or research of interest, become apparent. Broad trends indicate significant topics of the day, as well as the history relevant to both the work at hand, and particular areas of study.
Expanding the coverage of Web of Science, in November 2009 Thomson Reuters introduced Century of Social Sciences. This service contains files which trace social science research back to the beginning of the 20th century, and Web of Science now has indexing coverage from the year 1900 to the present. As of 24 February 2017[update], the multidisciplinary coverage of the Web of Science encompasses 12,000 high impact journals and 160,000 conference proceedings. The selection is made on the basis of
impact evaluations and comprise
academic journals, spanning multiple
academic disciplines. The coverage includes: the
the arts, and humanities, and goes across disciplines. However, Web of Science does not index all journals.
There is a significant and positive correlation between the
impact factor and
CiteScore. However, an analysis by
Elsevier, who created the journal evaluation metric CiteScore, has identified 216 journals from 70 publishers to be in the top 10 percent of the most-cited journals in their subject category based on the CiteScore while they did not have an impact factor. It appears that the impact factor does not provide comprehensive and unbiased coverage of high-quality journals. Similar results can be observed by comparing the impact factor with the
SCImago Journal Rank.
Furthermore, as of September 3, 2014 the total file count of the Web of Science was 90 million records, which included over a billion cited references. This citation service on average indexes around 65 million items per year, and it is described as the largest accessible citation database.
Titles of foreign-language publications are translated into English and so cannot be found by searches in the original language.
In 2018, the Web of Science started embedding partial information about the
open access status of works, using
2022 Russian invasion of Ukraine, on March 11, 2022, Clarivate – which owns Web of Science – announced that it would cease all commercial activity in Russia and immediately close an office there.
The Web of Science Core Collection consists of six online indexing databases:
Science Citation Index Expanded (SCIE) -previously entitled Science Citation Index- covers more than 9,200 journals across 178 scientific disciplines. Coverage is from 1900 to present day, with over 53 million records
citation indices listed above contain references which have been cited by other articles. One may use them to undertake cited reference search, that is, locating articles that cite an earlier, or current publication. One may search citation databases by topic, by author, by source title, and by location. Two chemistry databases, Index Chemicus and Current Chemical Reactions allow for the creation of structure drawings, thus enabling users to locate
chemical compounds and reactions.
Web of Science includes other products providing data, analytics, insights, workflow tools, and professional services to researchers, universities, research institutions, governments, private and public research funding organizations, publishers, and research-intensive corporations.
EndNote Click (formerly Kopernio) is a freely available
plugin allowing researchers to access papers in subscription-based
scientific journals, to which they are subscribed through their
higher education libraries, even when the user is off-campus. Using
artificial intelligence, the tool automatically records the institutional subscriptions each user has and searches for full-text versions of selected papers to which the user may have access.
Publons was a commercial website that provided a free service for academics to track, verify, and showcase their
peer review and editorial contributions for
academic journals. It was launched in 2012 and was bought by
Clarivate in 2017. It claimed that over 3,000,000 researchers joined the site, adding more than one million reviews across 25,000 journals. In 2019,
ResearcherID was integrated with Publons.
As with other scientific approaches,
bibliometrics have their own limitations. In 2010, a criticism was voiced pointing toward certain deficiencies of the
journal impact factor calculation process, based on Thomson Reuters Web of Science, such as: journal citation distributions usually are highly skewed towards established journals; journal impact factor properties are field-specific and can be easily manipulated by editors, or even by changing the editorial policies; this makes the entire process essentially non-transparent.
Regarding the more objective journal metrics, there is a growing view that for greater accuracy it must be supplemented with
article-level metrics and peer-review. Studies of methodological quality and reliability have found that "reliability of published research works in several fields may be decreasing with increasing journal rank". Thomson Reuters replied to criticism in general terms by stating that "no one metric can fully capture the complex contributions scholars make to their disciplines, and many forms of scholarly achievement should be considered."