• quality improvement
• clinical databases

Over the last decade there has been increasing pressure to make health care more accountable and to identify variations suggesting poor quality care which can be improved. While special studies can be conducted with these aims in mind, quality improvement activity will only become part of the fabric of health services if it can draw on data that are routinely collected. In North America extensive hospital data have been available; however, because they are generated as byproducts of administrative systems collected for other (usually financial) purposes, they are severely limited. Without the ability to adjust for patient case mix, for example, incorrect inferences about the cause of variations in patient outcomes are likely.¹ The sort of detailed clinical data needed to make sensible analyses …