Information on schools' performance is central to the school choice process in England. This paper evaluates school performance tables against criteria of functionality, relevance and comprehensibility. We estimate a model to judge functionality by setting up the following question: 'In which feasible school will my child achieve the highest exam score?'. We show that neither of the current leading performance measures scores very well. We propose an alternative measure which performs better on relevance and comprehensibility and not significantly worse on functionality. We demonstrate how the measure could be best delivered to parents. We also describe the trade-offs between the criteria of functionality and relevance and between comprehensibility and relevance.