Goodhart’s Law, as phrased by Mary Strathern: “When a measure becomes a target, it ceases to be a good measure.” Honored more in the breach than the observance, alas. Our algorithmic world has turned so many measures into targets, and by doing so ruined them. Let’s talk about just one example: let’s talk about books.

A young adult novel has been removed from the No 1 position on the New York Times bestseller lists, after detective work worthy of Nancy Drew by YA writers on Twitter uncovered a trail of strategic preorders being placed in particular US bookshops.