Rigorous policies ensure integrity of NLM literature databases

We read with interest the article titled “How predatory journals leak into PubMed,” by Dr. Manca and colleagues published in CMAJ.1 We thank the authors for their interest in PubMed and PubMed Central and provide clarification on which journals the US National Library of Medicine has selected for inclusion in these databases.

The premise of the article by Manca and colleagues is based on 2 of their previous studies, in which they suggest that a high number of “predatory” journals are accepted for indexing in PubMed or archiving in PubMed Central, and that the National Library of Medicine should “raise the bar for journal inclusion.”

However, Manca and colleagues have mistakenly characterized these journals as being included in PubMed and PubMed Central by conflating the appearance of 1 or more individual journal articles that are included in PubMed Central to support the public access policies of research funders,2^,3 with the inclusion of articles from an accepted journal. A journal is considered “accepted” and added to PubMed only if it has been formally assessed and recommended for indexing in MEDLINE or archiving in PubMed Central.

Moreover, the authors make several incorrect statements about PubMed and National Library of Medicine policies, most notably regarding journal selection criteria for PubMed Central. In fact, journals that apply to be in PubMed Central undergo a rigorous assessment of scientific and editorial quality,4 and the same assessment considerations are used to re-evaluate previously accepted journals.5 In addition, the National Library of Medicine reviews publishers of PubMed Central and MEDLINE journals for ongoing conformance with publishing guidelines and best practices.6

The National Library of Medicine is committed to the integrity of its literature databases and continues to develop its selection processes in response to changes in the scholarly publishing environment.