The work of the Centre for Development Impact (CDI) is focused on understanding and measuring social, political and economic impact – with a particular emphasis on the impact on the lives of the poorest and most marginalised. We are not tied to any one methodological approach, but rather the appropriateness of evaluation design and methods to a specific situation. We are particularly interested in broadening approaches, exploring innovations, and sharing learning around the assessment of impact.

We formally define impact evaluations as: 'evaluations that assess the contribution of an intervention towards some outcome or goal. The contribution may be intended or unintended, positive or negative, long-term or short-term. Impact evaluations attempt to identify a clear link between causes and effects, and explain how the intervention worked, and for whom'.

Importantly, in this definition we don’t limit impact evaluation to only experimental and quasi-experimental methodologies – although these can be important methodologies – but we still maintain a focus on understanding impact and causality.

There are a number of distinctive features to this definition:

  • Firstly, impacts can be unintended, positive or negative, long or short-term. The importance of longer-term, sustainable and transformational change is important when assessing impact, and is often overlooked in assessing three to five year interventions.
  • Secondly, the definition focuses on exploring the links between cause and effect, although importantly, this is not limited to a counterfactual understanding of causal inference. This characteristic, in particular, sets ‘impact evaluation’ apart from other types of organisational or process evaluation.
  • Thirdly, more equal weight given to understanding how the ‘impacts’ came about, as much as measuring the extent (size) of the impact.
  • And lastly, we focus on the importance of power dynamics, including who defines impact, and who is affected by the impact (the winners and losers). This is imperative as the impact on one socioeconomic group may negatively or disproportionately affect others in society.