Adverse events in health care: issues in measurement

Abstract

The principle that studying adverse events can produce information which leads to quality improvements is far from new and has been much used outside of health care.^{2, 3} It has an intuitive power—after all, we all learn much as individuals from our own mistakes, and it seems reasonable to hypothesise that organisations can also learn a great deal from their errors. However, it is easy to overlook the complexities of measurement involved in defining, classifying, identifying, describing, and analysing such adverse events.⁴ Like any other measurement tools, those used with adverse events need to be tested to ensure that they work. This article presents an analysis of the issues involved in defining adverse events, the sources of data which can be used to identify such events, and the validity and reliability of measures of quality based on adverse events in health care.