4.5 When and for which purpose to evaluate?

Evaluation can be used for a multitude of purposes and at different stages of an intervention.

Evaluation is often presented as a step in the policy cycle, taking place after the implementation of an intervention, intended to provide information to guide revisions as the cycle begins again. This representation is outdated and misleading. It doesn’t account for the vast potential of evaluation to contribute to policymaking at all stages of an intervention. Instead of sitting in the policy cycle between implementation and revisions, it is more appropriate to locate evaluation in the centre of the cycle, informing policy and program design, implementation and revisions.

Before an intervention is developed, evaluation can be used to identify needs and find the best fit for the contextual characteristics. Or, it can support the design stage of an intervention by identifying what would work best in a particular context, based on the scientific literature (logic analysis). Evaluation can be a process to optimize the design and implementation of the intervention in dynamic contexts, as in Developmental Evaluation (Patton, 2011), or to achieve transformational objectives as empowerment, emancipation, or advocacy (Brousselle & Champagne, 2011; Mertens, 2023). It can be used as a formative exercise to improve an intervention or its implementation, or as summative exercise to decide whether a program merits investment (Mark et al., 2000). It can guide decisions on what interventions to collectively support or stop funding, as in spending reviews or economic evaluations, for example). Evaluations “can be undertaken for the express purpose of supporting or building the image of a program” (Palumbo, 1987, p. 12). They can also contribute to the generation of generalizable knowledge (Brousselle et al., 2011b; Mark et al., 2000; Patton, 1997). These evaluative purposes are not exclusive, and an evaluation project can contribute knowledge for different purposes at different stages (Mark et al., 2000).