The world has changed fundamentally, according to the author Malcolm Gladwell, from one in which problems are puzzles to one in which they are, instead, mysteries. Using terminology developed by an intelligence official, Gregory Treverton, Gladwell said this distinction often centres on the amount of information available. In the past it was often about having too little data – a puzzle; in today’s world too much data is more likely to be the issue – a mystery. To take education as an example, today a wealth of data on how teachers perform is available, including on such complex is-sues as how a particular teacher’s methods interact with the capabilities of an individual student. Similar issues affect fields as diverse as defense and health care. This places challenges on institutions such as governments, because many developed their ways of operating in the 19th or even the 18th century. They are equipped to solve puzzles, not mysteries.