Broadening the range of designs and methods for impact evaluations: Report of a study commissioned by the Department for International Development

This is a study report dealing with difficult methodological and theoretical challenges faced by those who wish to evaluate the impacts of international development policies. Impact Evaluation (IE) aims to demonstrate that development programmes lead to development results, that the intervention as cause has an effect. Accountability for expenditure and development results is central to IE, but at the same time as policy makers often wish to replicate, generalise and scale up, they also need to accumulate lessons for the future. Explanatory analysis, by answering the ‘hows’ and ‘whys’ of programme effectiveness, is central to policy learning. On the basis of literature and practice, a basic classification of potential designs is outlined. Of the five design approaches identified - Experimental, Statistical, Theory-based, Case-based and Participatory, the study has in line with its ToR concentrated on the potential of the latter three. It is important to recognise that even when IE is inappropriate, enhancing results and impacts can still be addressed through evaluation strategies other than IE.