Investigating and improving patient safety in health care is now an international phenomenon. The establishment of the National Patient Safety Agency in the United Kingdom1 and of the Center for Quality Improvement and Patient Safety in the United States2 are prime examples of the prominence given to safety within the wider concept of healthcare quality. No longer can there be any doubt that the most fundamental ethical principle in medicine—first, do no harm—is being taken seriously by a wide constituency. The next step is to embed safe practice into everyday clinical behaviour.

Why is there so much interest in patient safety? Why now? Data have been available on error rates in medicine for at least a decade. Although there had been earlier work in the 1970s, the landmark Harvard Medical Practice study of hospital inpatients was published in 1991.3 Additional studies followed from Australia and other contexts.4 This research points to an adverse event rate in secondary care close to 10%. The error rate in primary care is less well studied.