I sometimes feel that if only politicians and civil servants had a “Ladybird Book of Randomised Policy Trials”, they'd understand why such trials were a brilliantly simple way for Whitehall to do more good, less harm and save money.

Well, I have hugely encouraging news to report: the “Ladybird Book of Randomised Policy Trials” now exists. Better than that, it's not just some academic flight of fancy. It is the result of a collaboration between two academic experts, Professor David Torgerson and Dr Ben Goldacre, and two civil servants, Laura Haynes and Owain Service, of the Cabinet Office's Behavioural Insights Team. In other words, something might actually happen.

My enthusiasm is scarcely dented by the fact that the document is actually called “Test, Learn, Adapt: Developing Public Policy with Randomised Controlled Trials”; no Ladybird, alas, although Goldacre tells me he wishes that had been the title.