Improving the peer review of narrative literature reviews

As the size of the published scientific literature has increased exponentially over the past 30 years, review articles play an increasingly important role in helping researchers to make sense of original research results. Literature reviews can be broadly classified as either "systematic" or "narrative". Narrative reviews may be broader in scope than systematic reviews, but have been criticised for lacking synthesis and rigour. The submission of more scientific manuscripts requires more researchers acting as peer reviewers, which requires adding greater numbers of new reviewers to the reviewing population over time. However, whereas there are many easily accessible guides for reviewers of primary research manuscripts, there are few similar resources to assist reviewers of narrative reviews. Here, I summarise why literature reviews are valued by their diverse readership and how peer reviewers with different levels of content expertise can improve the reliability and accessibility of narrative review articles. I then provide a number of recommendations for peer reviewers of narrative literature reviews, to improve the integrity of the scientific literature, while also ensuring that narrative review articles meet the needs of both expert and non-expert readers.