Randomised controlled trials (RCTs): Theory, methods and practice

What is a randomised controlled trial?

A randomised controlled trial (RCT) is a type of evaluation design that estimates the causal impact of an intervention on a sample by randomly allocating participants to either receive a form of intervention (intervention group) or (usually) to not receive an intervention (control group).

The impact of the intervention can be measured by comparing the outcomes of the intervention and control group.

RCTs are commonly used in research and evaluation but knowing how to use them can be a challenge.

Video explainer: What is an RCT?

Find out more about RCTs in our video explainer.

Case studies

We worked with King’s College London and the University of Leeds to develop two case studies, exploring causal impact in widening-participation settings:

Planning an RCT (webinar and guide)

Watch our webinar, part of the evaluating causal impact series.

Read this step-by-step guidance to learn about the key stages of running an RCT: Diagnose, Plan, Measure, Reflect.

RCTs: method and practice (webinar)

View our webinar session, ‘RCTs: method and practice’ part of our ‘Unlocking effective evaluation’ series in 2022. Hear from evaluation experts about RCTs and how they can be implemented. It includes:

• RCTs – theory and background
• Summer schools project – a practical example
• Early findings
• Q&A