If at first you don’t succeed, goes the old saying, try, try again. Good advice, up to a point. But let me offer a modification: even when you do succeed, try, try again. Tempting as it is to declare victory and move on, in many endeavours there is much to be said for rethinking an apparently satisfactory formula.

Consider the advice for job interviewers in Talent, a new book by economist Tyler Cowen and venture capitalist Daniel Gross. They suggest asking a routine question, such as “give me an example of when you resolved a difficult challenge at work”. Then ask for another example. And another. The pat answers will be exhausted quickly, and the candidate will have to start improvising, digging deep — or perhaps admit to being stumped.

“If the candidate really does have 17 significant different work triumphs,” write Cowen and Gross, “maybe you do want to hear about what number 17 looks like.”