From a new report by the Behavioural Insights Unit at the British government (with Ben Goldacre and David Torgerson) on using RCTs in policy.
Randomised controlled trials (RCTs) are the best way of determining whether a policy is working. They are now used extensively in international development, medicine, and business to identify which policy, drug or sales method is most effective. They are also at the heart of the Behavioural Insights Teamʼs methodology. However, RCTs are not routinely used to test the effectiveness of public policy interventions in the UK. We think that they should be.(HT: Tim Harford's twitter feed)