For research evidence to inform decision making, an appraisal needs to be made of whether the claims are justified and whether they are useful to the decisions being made. This chapter provides a high level framework of core issues relevant to appraising the "fitness for purpose" of evidence claims. The framework includes (I) the variation in the nature of research, the evidence claims it produces, and in the values, perspectives, and ethical issues that underlie it; (II) the main components of the bases of evidence claims in terms of (i) how relevant evidence has been identified and synthesized to make a claim, (ii) the technical quality and relevance of the included evidence, and (iii) the totality of evidence to justify the warrant of the evidence claim (including the potential for there to be alternative explanations); (III) evidence standards to appraise evidence claims and examples of guides and tools to assist with aspects of such appraisal; and (IV) engagement with evidence: (i) the communication of evidence claims, (ii) the fitness for purpose of these evidence claims for decision makers, and (iii) and the interpretation of such claims to provide recommendations and guidance.