Evaluation relies on a combination of facts and values (i.e., principles, attributes or qualities held to be intrinsically good, desirable, important and of general worth1 such as ‘being fair to all’) to judge the merit of an intervention (i.e., a programme or policy). Evaluative criteria specify the values that will be used in an evaluation. While evaluative criteria can be used in different types of evaluations, this brief specifically addresses their use in impact evaluations (i.e., studies that provide information about the long-term effects produced by an intervention; see Brief No. 1, Overview of Impact Evaluation). UNICEF uses a range of evaluative criteria to guide its evaluations; not all of them are used in every evaluation, as some are appropriate to certain interventions and/or types of evaluation only. The Terms of Reference (ToR) for the evaluation must specify the relevant evaluative criteria to use.