This article is number 5 in a series of 21 articles on tools for evidence-informed health policymaking. Systematic reviews are increasingly seen as a key source of information to inform policymaking, particularly in terms of assisting with characterising the impacts of policy and programme options. They offer a number of advantages over single studies in characterising impacts and are also becoming a key source of information to assist with defining problems and providing complementary characterisations of options. Systematic reviews can be undertaken to place problems in comparative perspective, and to characterise the likely harms of an option. They also assist with understanding: the meanings that individuals or groups attach to a problem, how and why options work, and the views and experiences of stakeholders about particular options. A number of constraints have hindered wider use of systematic reviews in policymaking, including:

1. A lack of awareness of their value

2. Challenges in retrieving systematic reviews using search terms with which policymakers are familiar but which may not have been used in the original reviews, and

3. Challenges in understanding systematic reviews that are written in a way that does not adequately highlight (or make obvious) the types of information that policymakers are seeking.