Probing for proof, plausibility, principle and possibility: a new approach to assessing evidence in a systematic evidence review

This article proposes a new approach to assessing evidence during a systematic evidence review aiming to inform international development policy. Drawing lessons from a number of social science systematic evidence reviews, the paper identifies how the method’s limiting perspective on evidence (including the exclusive focus on ‘golden standard’ empirical information) has serious disadvantages for the usability of evidence reviews for policy. This article aims to provide an alternative framework that allows for a less exclusionary, yet policy-practical way of assessing evidence. We propose four perspectives on evidence, appropriate for different stages in the policy process: principle when setting or prioritising broad policy goals, plausibility when assessing specific future policies, proof when evaluating past policies and possibility when striving for innovation and allowing exchange of ideas.