Systematic reviews: A glossary for public health

Literature reviews are conducted for a range of purposes, from providing an overview or primer of a novel topic, to providing a comprehensive, precise, and accurate estimate of an effect estimate. There is much confusion over nomenclature related to literature reviews, with the term 'systematic review' often used to mean any review based on some form of explicit methodology. However, guidance and minimum standards exist for these kinds of robust reviews that are intended to support evidence-informed decision-making, and reviewers must carefully ensure their syntheses are conducted and reported to a high standard if this is their objective. The diversity of names given to reviews is reflected in the diversity of methods used for these evidence syntheses: the result is a general confusion about what is important to ensure a review is fit-for-purpose, and many reviews are labelled as 'systematic reviews' when they do not follow standardised or replicable approaches. Here, we provide a glossary or typology that aims to highlight the importance of the reviewers' objectives in choosing and naming their review method. We focus on reviews in public health and provide guidance on selecting an objective, methodological guidance to follow, justifying and reporting the methods chosen, and attempting to ensure consistent and clear nomenclature. We hope this will help review authors, editors, peer-reviewers, and readers understand, interpret, and critique a review depending on its intended use.