This type of search is often done in addition to standard database searching, to increase the recall of all the relevant literature. However, this method should not be used in isolation when searching for evidence as large amounts of information could be missed.
Citation searching uses one relevant publication to locate others, by exploring the list of references at the end of the publication in the bibliography (going back in time and reading what the authors read to inform the article), and by exploring other publications that cite your reference (going forward in time and reading subsequent publications that listed your reference in their bibliography).
Where to do citation searches
Certain subscription databases have a citation index created from the lists of references that appear at the end of journal articles. This means you can also find articles that cite that journal article, as well as the articles which that article references.
- Web of Science (from Thomson Reuters – includes the three original citation indexes, including the Science Citation Index)
- Scopus (from Elsevier – the main competitor to Web of Science)
More recently, other online journal collections and databases have included citation indexes, notably:
A free option, that does not require subscription:
Google Scholar now offers citation information on search results, though given the different coverage of Google Scholar from bibliographic databases, these results may not tally with those of the formal, bibliographic databases (i.e. Google Scholar comprises automatically generated lists which include pre-prints and non-reviewed websites, as opposed to the curated, published and peer-reviewed content in Web of Science for example).
How to do citation searches
Choose a key publication that is highly relevant to your search (and ideally more than two years old). Then, in one of the tools listed above, conduct a search for this article (e.g. an author/ title search or use “Cited Reference Search”). The citations relating to your article will be accessible via links called variably “Citation network”, “Cited By”, or “Related Articles”.
Advantages of citation searching
Citation searching can turn up publications that were not found via standard database searches because you are not constrained by the vocabulary of a search strategy or bibliographic record. You may also find articles from unexpected disciplines.
But the main advantage of citation searching is that you can follow a line of scholarly communication on a given topic over time, by going backward and forward from a seed reference. You may also be able to gauge the impact of a publication by looking at the citation count, the logic being that articles that are frequently cited have had greater impact or influence in the scientific community (though of course there will be exceptions to this).