Randomized controlled trials (RCTs)

This guide, written by Howard White, Shagun Sabarwal and Thomas de Hoop for UNICEF, looks at the use of Randomized Control Trials (RCTs) in Impact Evaluation.

The paper gives an overview of RCTs and then outlines when it is appropriate to use it, provides examples of using the method and outlines some of the problems that may be encountered when using RCTs in impact evaluation.


"A randomized controlled trial (RCT) is a way of doing impact evaluation in which the population receiving the programme or policy intervention is chosen at random from the eligible population, and a control group is also chosen at random from the same eligible population. It tests the extent to which specific, planned impacts are being achieved.

In an RCT, the programme or policy is viewed as an ‘intervention’ in which a treatment – the elements of the programme/policy being evaluated – is tested for how well it achieves its objectives, as measured by a predetermined set of indicators. The strength of an RCT is that it provides a very powerful response to questions of causality, helping evaluators and programme implementers to know that what is being achieved is as a result of the intervention and not anything else."



  • Randomized controlled trials: a brief description
  • When is it appropriate to use this method?
  • How to conduct a randomized controlled trial
  • Ethical issues and practical limitations
  • Which other methods work well with this one?
  • Presentation of results and analysis
  • Example of good practices
  • Examples of challenges 


White, H., Sabarwal, S., & de Hoop, T. (2014). Randomized Controlled Trials (RCTs). UNICEF. Retrieved from: http://devinfolive.info/impact_evaluation/img/downloads/Randomized_Controlled_Trials_ENG.pdf

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