4. How do I search for the evidence?

4.8. Citation searching

5.8 Citation searching

Citation searching is a powerful method for finding publications relating to your field of research, which might not be found using conventional search strategies.

This type of search is often done in addition to standard database searching, to increase the recall of all the relevant literature.

Find one relevant publication and you can locate others by ‘time travelling’:

Go back in time

Explore the list of references at the end of the publication to explore the literature that informed the author(s).

Go forward in time

Explore newer publications that ‘cite’ the publication (see How to do citation searches below).

The metaphor 'citation pearl growing' describes citation searching, as it’s like seeing a single grain of sand (your one useful publication) grow into a beautiful pearl (a list of many useful references).


This method should not be used in isolation when searching for evidence as large amounts of information could be missed.

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)

A freely available option is:

Google Scholar offers citation information in the search results.

The results of Google Scholar may not tally with those of the formal, bibliographic databases, since they have different coverage: Google Scholar citations are found online so may include pre-prints, conferences, non-indexed publications and non-reviewed websites; by contrast, Web of Science and Scopus citations are curated from a specific list of publications.

How to do citation searches

Step 1. Choose a key publication that is highly relevant to your search

A brand-new publication usually doesn’t work as well because researchers need time to find the publication you are searching for citations of, read it, write something of their own that includes your article in the references, and publish their piece.

Step 2. In one of the tools listed in 'Where to do citation searches', conduct a search for your article (for example, an author/title search or use 'Cited Reference Search').

Step 3. The citations relating to your article will be accessible via links called variably 'Citation network', 'Cited By', or 'Related Articles'.

  • You can follow a line of scholarly communication on a given topic over time.

  • You can find publications that were not found via standard database searches.

  • You are not constrained by the vocabulary of a search strategy or bibliographic record. You may also find articles from unexpected disciplines.

  • You can go backward and forward from a ‘seed’ reference.

  • You can gauge the ‘impact’ of a publication by looking at the citation count; articles that are frequently cited have had greater impact or influence in the scientific community (though of course there will be exceptions to this, for example, papers which are disputed can be heavily cited, so you still need to appraise the paper yourself).