Impact assessment and the quest for the Holy Grail

Working Paper Series 2015 – 3


Roger Bymolt

Evaluation is seen as vital for both accountability and learning purposes. This involves understanding not only what worked but also the process of change and why and how an intervention worked. Donors, programme managers and evaluators often claim to seek not only successful outcomes, but the ‘holy grail’ of impact. This paper surveys the minefield of what impact is and how it can be reliably assessed, from the perspectives of proponents favouring (quasi)experimental, quantitative designs to those oriented towards the qualitative.