Medical literature searches: a comparison of PubMed and Google Scholar

Abstract

Background: Medical literature searches provide critical information for clinicians. However, the best strategy for identifying relevant high-quality literature is unknown. Objectives: We compared search results using PubMed and Google Scholar on four clinical questions and analysed these results with respect to article relevance and quality. Methods: Abstracts from the first 20 citations for each search were classified into three relevance categories. We used the weighted kappa statistic to analyse reviewer agreement and nonparametric rank tests to compare the number of citations for each article and the corresponding journals' impact factors. Results: Reviewers ranked 67.6% of PubMed articles and 80% of Google Scholar articles as at least possibly relevant (P = 0.116) with high agreement (all kappa P-values < 0.01). Google Scholar articles had a higher median number of citations (34 vs. 1.5, P < 0.0001) and came from higher impact factor journals (5.17 vs. 3.55, P = 0.036). Conclusions: PubMed searches and Google Scholar searches often identify different articles. In this study, Google Scholar articles were more likely to be classified as relevant, had higher numbers of citations and were published in higher impact factor journals. The identification of frequently cited articles using Google Scholar for searches probably has value for initial literature searches.

Google Scholar is not enough to be used alone for systematic reviews

“…A consensus seemed to emerge that GS was not as current as PubMed and some expert searchers placed it a year behind or more [7]. Searchers also noticed that PubMed and Google Scholar fulfilled different purposes [10]. In head-to-head comparisons with curated databases, GS was deemed inadequate for subject searching and did not offer what expert searchers wanted to see in a literature database.…”

Empirical evidence on legal levers aimed at addressing child maltreatment

“…Web of Science is a standard search engine for identifying peer-reviewed studies. Google Scholar was preferred over PubMed because a previous study comparing both search engines revealed that articles found using Google Scholar were more relevant, had more citations, and were published in journals with higher impact scores (Nourbakhsh, Nugent, Wang, Cevik, & Nugent, 2012). Inclusion criteria required that the study be published in a peer review outlet, focused on a U.S. sample, and examined the extent to which a change in the law or practice was causally related to change in maltreatment prevalence or incidence.…”

Clinical calculators in hospital medicine: Availability, classification, and needs

“…Dedicated online resources with clinical calculators and providers of aggregated medical information were used (UpToDate, Merck/Univadis, and Medscape) [12][13][14]. Names of available clinical calculators were extracted.…”