Introduction to impact evaluation

Available languages

This guidance note from InterAction outlines the basic principles and ideas of Impact Evaluation including when, why, how and by whom it should be done. The document is available in English, French, Spanish and Arabic.

Included with the paper are links to the following webinars and slideshows:

Webinar #1: Introduction to Impact Evaluation, with Patricia Rogers: 

Webinar #2: Impact Evaluation: NGO Perspectives, with Oxfam America and Save the Children:



What Do We Mean by “Impact Evaluation”? 

  • Why Should We Do Impact Evaluation? 
  • What Questions Does Impact Evaluation Seek to Answer? 
  • Who Should Conduct Impact Evaluation? 
  • How Should We Choose Methods for Impact Evaluation? 
  • Clarifying Values for an Impact Evaluation 
  • Developing a Theory or Model of How the Intervention is Supposed to Work 
  • Measuring or Describing Impacts (and other Important Variables) 
  • Explaining to What Extent Observed Results Have Been Produced by the Intervention 
  • Synthesizing Evidence 
  • Reporting Findings and Supporting Use 
  • When Should an Impact Evaluation Be Done? 
  • What Is Needed for Quality Impact Evaluation? 
  • Common Challenges in Impact Evaluation in Development


Rogers, P. J. InterAction, (2012). Introduction to impact evaluation (No. 1.). Retrieved from website:


' Introduction to impact evaluation' is referenced in: