Appraisal of: “Janssens C, Gwinn M, Brockman JE, Powell K, Goodman M. Novel citation-based search method for scientific literature: a validation study. PeerJ Preprints 2019;7:e27646v1"

Reviewer(s): 
Short description: 

The authors developed CoCites, a citation-based search method that is designed to be more efficient than traditional keyword-based methods. The method begins with identification of one or more highly relevant publications (query articles) and consists of two searches: the co-citation search, which ranks publications on their co-citation frequency with the query articles, and the citation search, which ranks publications on frequency of all citations that cite or are cited by the query articles.

The approach was validated and achieved in a sample of 250 systematic reviews a median sensitivity of 75%. CoCites’ co-citation and citation searches combined retrieved 88% of included articles when all were in PubMed.

Limitations stated by the author(s): 

1) we assumed that articles in the reviews were correctly included and excluded; however, it is possible that CoCites missed articles that should not have been included in the review and retrieved relevant articles that the authors had missed. If erroneous inclusion of articles is common, the performance of CoCites is underestimated.

2) the authors of original reviews often utilized multiple sources, including foreign and specialty databases, conference proceedings, dissertations, and personal communications. The sources might yield articles that cannot be found through PubMed, WOS, or other major English-language literature databases. Therefore, it is not realistic to expect a 100% retrieval. When CoCites is used to find relevant articles for systematic reviews and meta-analyses, these additional sources may still need to be searched, if the topic so requires.

3) we found that co-citation searching might not retrieve articles that are infrequently cited. These articles are more likely to include abstracts, letters, articles in non-English languages, and very old articles, reports, and theses that may not be indexed in WOS or other databases. Infrequently cited papers also include articles in WOS that were published too recently to be cited or that authors did not consider worth citing.

Limitations stated by the reviewer(s): 
The article was published without peer review.
Study Type: 
Single study