About Nesta

Nesta is an innovation foundation. For us, innovation means turning bold ideas into reality and changing lives for the better. We use our expertise, skills and funding in areas where there are big challenges facing society.

Randomising your participants can be quite straightforward once you know how. The main thing you need is a list of participants in a spreadsheet (either Excel or Google Sheets). You can use our randomisation guides (links below) to turn this into a randomised list.

In a simple trial, there are usually two groups: the intervention group exposed to your new policy, and the control group that gets the business-as-usual policy. However, there can be many more groups in complex trials testing out different changes against one another.

How to randomise

You can randomise a list of participants in three simple steps:

  1. Generate a random number for each participant
  2. Sort the random numbers in numerical order
  3. Categorise your list into control and intervention groups

We have produced two short guides to walk you through this process. You can download them below. Begin with the Word guide to explain the process, and then practice using the Excel guide:

  1. Word guide
  2. Excel guide

You can also watch the short video below, which walks you through how to do it.

What to randomise?

At the beginning of your trial you need to decide the unit of randomisation. In the case of a trial looking at take-up rates of childcare within a local area, individual randomisation – randomising parents or carers to receive either the intervention or business-as-usual – is probably the most appropriate way to do it. But other trials will be different. For example, you could conduct a trial where children’s centres are the unit of randomisation; some children’s centres deliver a new intervention and some continue to deliver ‘business as usual’.

Authors

Louise Bazalgette

Louise Bazalgette

Louise Bazalgette

Deputy Director, fairer start mission

Louise works as part of a multi-disciplinary innovation team focused on narrowing the outcome gap for disadvantaged children.

View profile
Dave Wilson

Dave Wilson

Dave Wilson

Advisor

Dave is an Advisor in the Education team at the Behavioural Insights Team (BIT) with a focus on early years projects.

View profile
Fionnuala O’Reilly

Fionnuala O’Reilly

Fionnuala O’Reilly

Lead Behavioural Scientist, fairer start mission

Fionnuala was the lead behavioural scientist in the fairer start mission, seconded from the Behavioural Insights Team (BIT).

View profile