The Health and Social Care Bill1 will give up to 300 general practitioner consortia in England the power and money (£80 billion) to commission services from NHS hospitals and private providers. Their decisions will be informed by data on activity, performance and patient outcomes. The main source of data will be hospital episode statistics (HES),2 supplemented by separately collected patient recorded outcomes.3 These data will also inform patients and enable them to make choices regarding their hospital, consultant and treatment.4 It has also been suggested that HES could support the monitoring of quality through national audits,5 individual consultant appraisal6 and research through linkage to other datasets.7

Historically, the process for collecting data for HES has been geared towards supporting the corporate business of the NHS. The uses have been administrative—to monitor activity and performance, identify costs and allocate resources8—and epidemiological, particularly at a large area level.9,–,12 As the range of uses has grown, and become more clinical, the quality of the data held in HES …