International development is often complex, and evaluating the effectiveness of development investments can be highly problematic. These issues are well illustrated through efforts to assist vulnerable communities respond to uncertain but potentially damaging global change issues such as water, food and energy security, and climate impacts.

Many assumptions about the direct relationship between an intervention and its impact can be weak or even untested, presenting challenges for the thorough evaluation of investment efforts. This is of course problematic for evaluations that seek to accurately describe impact/pathway to impact at project completion or soon after; and has led to some justified criticism of a number of impact evaluation approaches. In response, governments and development agencies worldwide are increasing emphasis on measurable goals, metrics, and the performance of investments in development assistance.

We report on the findings of a novel impact evaluation methodology that draws on a range of qualitative and quantitative approaches that delivers an improved understanding of: how aid investment in R4D can deliver impact; the benefits of research to improve development outcomes; and the value of better targeting investment to support development outcomes in contexts of rapid change and uncertainty. We demonstrate that impacts can be successfully tested for at project completion and measured over time to elicit greater confidence levels for impact pathways. The methodology provides a dynamic and powerful tool to assist decision-makers with evidence-based program and portfolio investment choices, and to our knowledge, is the only product of this type in use.