Reducing mishaps from medical management is central to efforts to improve quality and lower costs in health care. Nearly 100 000 patients are estimated to die preventable deaths annually in hospitals in the United States, with many more incurring injuries at an annual cost of $9 billion. Underreporting of adverse events is estimated to range from 50%-96% annually.1^–3 This annual toll exceeds the combined number of deaths and injuries from motor and air crashes, suicides, falls, poisonings, and drownings.4 Many stakeholders in health care have begun to work together to resolve the moral, scientific, legal, and practical dilemmas of medical mishaps. To achieve this goal, an environment fostering a rich reporting culture must be created to capture accurate and detailed data about nuances of care.

Outcomes in complex work depend on the integration of individual, team, technical, and organisational factors. 5 6 A continuum of cascade effects exists from apparently trivial incidents to near misses and full blown adverse events. 7 8 Consequently, the same patterns of causes of failure and their relations precede both adverse events and near misses. Only the presence or absence of recovery mechanisms determines the actual outcome.9 The National Research Council defines a safety “incident” as an event that, under slightly different circumstances, could have been an accident.10 Focusing on data for near misses may add noticeably more value to quality improvement than a sole focus on adverse events.

Schemes for reporting near misses, “close calls,” or sentinel (“warning”) events have been institutionalised in aviation,^{w1 w2} nuclear power technology,^{w3 w4} petrochemical processing, steel^w5 production,^w6 military operations, and air transportation.^w7-w11 In health care, efforts are now being made to create incident reporting systems for medical near misses 8 11^–15 to supplement the limited …