How are evidence and policy conceptualised, and how do they connect? A qualitative systematic review of public policy literature

Background: While current public policy scholarship can take advantage of a decades-long accumulated knowledge base on the relationship between evidence and policy, it is hard to keep the overview across different literatures. Over time, the ever more differentiated branches of public policy research have developed their own perspectives, languages, and conceptualisations of 'evidence' and 'policy', as well as their connections. Aims and objectives: Existing reviews have stressed that studies often do not provide clear definitions of 'policy' or 'evidence', and have outlined the importance of investigating underlying conceptualisations in the literature. Against this backdrop, this article investigates how present-day public policy scholarship approaches the concepts of 'evidence', 'policy', and their connections. Methods: We conducted a qualitative systematic review following the PRISMA method. Using a keyword search, we identified relevant articles (n=85) in eleven Q1 and Q2 policy journals included in Web of Science in the period 2015 to 2019. Findings: The synthesis confirms that 'evidence' and 'policy' are often not clearly defined, yet different trends regarding understandings can be identified. There are two approaches taken on the evidence and policy connection: a 'use of evidence' or a 'use for policy' perspective. Discussion and conclusions: Research on evidence and policy would benefit from more explicit conceptual discussions. This review may provide a heuristic for explicating conceptual choices when working with the notions of 'evidence', 'policy', and their connections. It also suggests several avenues that are worth exploring in future research.