Quantitative and Qualitative Methods in Impact Evaluation and Measuring Results

Governance and Social Development Resource Centre. Issues Paper by Sabine Garbarino and Jeremy Holland March 2009

1 Introduction
There has been a renewed interest in impact evaluation in recent years amongst development agencies and donors. Additional attention was drawn to the issue recently by a Center for Global Development (CGD) report calling for more rigorous impact evaluations, where ‘rigorous’ was taken to mean studies which tackle the selection bias aspect of the attribution problem (CGD, 2006). This argument was not universally well received in the development community; among other reasons there was the mistaken belief that supporters of rigorous impact evaluations were pushing for an approach solely based on randomised control trials (RCTs). While ‘randomisers’ have appeared to gain the upper hand in a lot of the debates—particularly in the United States—the CGD report in fact recognises a range of approaches and the entity set up as a results of its efforts, 3ie, is moving even more strongly towards mixed methods (White, nd). The Department for International Development (DFID) in its draft policy statements similarly stresses the opportunities arising from a synthesis of qualitative and qualitative approaches in impact evaluation. Other work underway on ‘measuring results’ and ‘using numbers’ recognises the need to find standard indicators which capture non-material impacts and which are sensitive to social difference. This work also stresses the importance of supplementing standard indicators with narrative that can capture those dimensions of poverty that are harder to measure. This paper contributes to the ongoing debate on ‘more and better’ impact evaluations by highlighting experience on combining qualitative and quantitative methods for impact evaluation to ensure that we:

1. measure the different impact of donor interventions on different groups of people and

2. measure the different dimensions of poverty, particularly those that are not readily quantified but which poor people themselves identity as important, such as dignity, respect, security and power.

A third framing question was added during the discussions with DFID staff on the use of the research process itself as a way of increasing accountability and empowerment of the poor.

This paper does not intend to provide a detailed account of different approaches to impact evaluation nor an overview of proposed solutions to specific impact evaluation challenges. Instead it defines and reviews the case for combining qualitative and quantitative approaches to impact evaluation. An important principle that emerges in this discussion is that of equity, or what McGee (2003, 135) calls ‘equality of difference’. By promoting various forms of mixing we are moving methodological discussion away from a norm in development research in which qualitative research plays ‘second fiddle’ to conventional empiricist investigation. This means, for example, that contextual studies should not be used simply to confirm or ‘window dress’ the findings of non-contextual surveys. Instead they should play a more rigorous role of observing and evaluating impacts, even replacing, when appropriate, large-scale and lengthy surveys that can ‘overgenerate’ information in an untimely fashion for policy audiences.

The remainder of the paper is structured as follows. Section 2 briefly sets the scene by summarising the policy context. Section 3 clarifies the terminology surrounding qualitative and quantitative approaches, including participatory research. Section 4 reviews options for combining and sequencing qualitative and quantitative methods and data and looks at recent methodological innovations in measuring and analysing qualitative impacts. Section 5 addresses the operational issues to consider when combing methods in impact evaluation. Section 6 briefly concludes.

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