The case for laboratory experiments in behavioural public policy

Behavioural science is increasingly applied to policy in many countries. While the empirical approach to policy development is welcome, we argue with reference to existing literature that laboratory experiments are presently underused in this domain, relative to field studies. Assumptions that field experiments, including randomised controlled trials, produce more generalisable results than laboratory experiments are often misplaced. This is because the experimental control offered by the laboratory allows underlying psychological mechanisms to be isolated and tested. We use examples from recent research on energy efficiency and financial decision-making to argue that mechanism-focused laboratory research is often not only complementary to field research, but also necessary to interpreting field results, and that such research can have direct policy implications. The issues discussed illustrate that in some policy contexts a well-designed laboratory study can be a good – perhaps the best – way to answer the kinds of research questions that policy-makers ask.