The special issue that you see before you – on the development and use of field experiments in public policy – comes at an opportune moment, as the topic informed who would win the 2019 Nobel Memorial Prize in the Economic Sciences. The proposal for this special issue was sent to us by Professor John List a few years ago. List has probably done more than anyone else to advance the methods and practice of field experiments, and he and his colleagues Omar Al-Ubaydli, Min Sok Lee, Claire L. Mackevicius and Dana Suskind contribute the lead article to this special issue (hereafter, Al-Ubaydli et al.).

The lead article discusses several issues and challenges that ought to be addressed so that field experiments can better help to inform public policy and practice. The special issue then proceeds with eight reflections on the content of the lead article, which are ordered from the supportive and constructive, to the slightly more critical, eventually to the view that field experiments probably should not inform public policy at all. The issue finishes with a short article by Al-Ubaydli et al. that reflects upon these reflections.

Field experiments are, we feel, here to stay, and although they do not have to be restricted in their use to behavioural interventions, they have become an important tool within the behavioural public policy toolbox. Over time, despite the many legitimate (and less legitimate) concerns that are held regarding their use, they are likely to become more important still.