We argue that non-experimental impact estimators will continue to be needed for evaluations of interventions in developing countries as social experiments, for various reasons, will never be the most preferred approach. In a survey of four studies that empirically compare the performance of experimental and non-experimental impact estimates using data from development interventions, we show that the preferred non-experimental estimators are unbiased. We try to explain the reasons why the non-experimental estimators perform better in the context of development interventions than American job-market interventions. We also use the survey as a source for suggestions for implementation and assessment of non-experimental impact evaluations. Our main suggestion is to be more careful and precise in the formulation of the statistical model for the assignment into the program and also to use the assignment information for model-based systematic sampling.

The focus on results in development agencies has led to increased focus on impact evaluation to demonstrate the effectiveness of development programmes. A range of methods are available for counterfactual analysis of infrastructure interventions, as illustrated by the variety of papers in this volume. Understanding impact means understanding the context in which an intervention takes place and the channels through which the impact on outcomes is expected to occur. Such analysis typically requires mixing both quantitative and qualitative approaches. The analysis will also anticipate heterogeneity, with conditioning for 'selection bias' being recognised as positive information about for whom and when an intervention works or not.impact evaluation, infrastructure, counterfactual,

There is an urgent need to better understand the role that the use of blended finance in development co-operation can play in achieving the Sustainable Development Goals (SDGs). By adopting the "Blended Finance Principles for Unlocking Commercial Finance for the SDGs" in 2017, members of the OECD's Development Assistance Committee committed to "monitor blended finance for transparency and results". The practical implications of monitoring and evaluating blended finance are currently being explored with a view to providing further policy guidance on the implementation of these Principles. This paper contributes to the ongoing consultation process by discussing governance and methodological challenges in blended finance evaluation and proposing a few options to deal with them.

Part of the justification for joint-donor evaluations is that they allow the conduct of relevant evaluations with a broader scope than single-donor evaluations and at the same time reduce transaction costs. Many joint-donor evaluations, however, run into management and coordination problems, have unforeseen high transaction costs for the donors and result in general conclusions and recommendations. The purpose of this article is to contribute to a better understanding of the factors that influence how donor-evaluation units engage in joint evaluations and to identify mechanisms that can make them more effective. It represents a first step towards analysing joint evaluations using a political-economy perspective based on assumptions about the interests and incentives of donor management, evaluations units and evaluators. The article argues that the broader scope of many joint-donor evaluations and their relatively high transaction costs are closely related to and originate from differences in donor interests and incentive structures, and an insufficient focus on methodological challenges. The article concludes with a number of tentative operational suggestions based on the analyses.

A lively methodological debate together with organisational adjustments has dominated the international discussion on development evaluation in the last decade. Less discussed have been the evaluation processes, from procurement of consultants to the completion of evaluations, where many donors have used the same ‘system’ with only minor adjustments for many years. A key question is whether this ‘system’ is still ‘fit for purpose’ in view of the increasing complexity of many development interventions. This article presents three perspectives on development evaluation processes – the ‘independence perspective’, the ‘transaction cost perspective’ and the ‘political economy perspective’ – and argues that in particular the ‘political economy perspective’ constitutes a relevant perspective in analyses of evaluation processes. It is concluded that evaluation processes should be designed to reflect the specific characteristics of the individual evaluations, but also that more analysis and experimentation are required.