Presenter(s): Giel Ton, LEI Wageningen UR, giel.ton@wur.nl Marieke De Ruijter De Wildt, LEI Wageningen UR, marieke.deruijterdewildt@wur.nl
Abstract: Impact evaluations of value chain interventions are challenging: outcome indicators are often multi-dimensional, impact is generated in dynamic and open systems, and the social embeddedness constraints external validity. Therefore, there is a strong case for theory-based evaluation where a logic model indicates how the intervention is expected to influence the incentives for people’s behaviour. The key assumptions inherent in these casual models can be tested through the observation and measurement of specific outcome indicators using mixed methods in triangulation. The paper presents a framework to evaluate the design of these mixed methods to assess change and impacts in value chain configurations, using the four types of validity threats to the evaluative conclusion. We apply the framework on three impact assessment experiences, we have been involved in, and reflect on the feasibility to improve its methodological design: micro-irrigation technology supply; farmer field schools; business service development.