For many years, question choice has been used in some UK public examinations, with students free to choose which questions they answer from a selection (within certain parameters). There has been little published research on choice of exam questions in recent years in the UK. In this article we distinguish different scenarios in which choice arises, explore the arguments for and against using optional questions, and exploit the item level data that has recently become available from on-screen marking of examinations to exemplify methods for investigating the (statistical) comparability of optional questions. We conclude that unless there is a very good reason for allowing question choice it should be avoided.