Overview of impact evaluation

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This paper, written by Patricia Rogers for UNICEF, outlines the basic ideas and principles of impact evaluation.

It includes a discussion of the different elements and options for the different stages of conducting an impact evaluation.


"Impact evaluations provide information about the impacts produced by an intervention. Impact evaluation can be undertaken of a programme or a policy, or upstream work – such as capacity building, policy advocacy and support for an enabling environment. This goes beyond looking only at goals and objectives to also examine unintended impacts. OEDC-DAC defines impacts as “positive and negative, primary and secondary long-term effects produced by a development intervention, directly or indirectly, intended or unintended.”

An impact evaluation can be undertaken for formative purposes (to improve or reorient a programme or policy) or for summative purposes (to inform decisions about whether to continue, discontinue, replicate or scale up a programme or policy). It can be used by UNICEF and its partners at the global, regional or country level to inform decisions and for advocacy and advice."



  • What is impact evaluation - and why does it matter?
  • Deciding to conduct an impact evaluation
  • Establishing governance and management arrangements
  • Preparing to conduct the impact evaluation
  • Developing a terms of reference (tor) for the evaluation
  • Engaging the evaluation team
  • Overseeing the evaluation
  • Following up the evaluation
  • Anticipating and addressing ethical issues
  • Ensuring a quality impact evaluation


Rogers,P. (2014). Overview of Impact Evaluation. UNICEF. Retrieved from: http://devinfolive.info/impact_evaluation/img/downloads/Overview_ENG.pdf


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