Accidental deaths, saved lives, and improved quality.

More than five years ago, the Institute of Medicine (IOM) issued its pathbreaking report, To Err Is Human, and fundamentally changed the debate about health care quality in the United States.1 The publication reconfigured how we think about the quality of care, attracted greater interest among payers and employers in the improvement of care and patient safety, focused attention on the need to inform patients who have been victims of iatrogenic injury, and produced a substantial increase in research support. The report recently has been characterized as the most influential health care publication in the past two decades.2 Yet at this point, there is a sense of disappointment about the results of the patient-safety movement. There have been few breakthrough interventions. There is little evidence that the health care system is safer today than it was five years ago and certainly nothing to suggest that deaths from error have been cut in half, as the IOM called for in its report. Leading advocates have not found evidence of the transformation of the health care system, or even of individual hospitals, that was thought necessary to make the health care system as safe as other industries.3-5 Hence, the answer to the question being asked five years later — how many deaths have been prevented? — is disappointing. But so is the question. The problem lies in an overreliance on the notion of the individual accidental death. This notion oversimplifies the causal realities of iatrogenic injuries, overpromises on achievable gains, and threatens to skew priorities in quality-improvement initiatives. Moving away from a focus on saving lives solely by preventing errors and instead emphasizing the implementation of evidence-based practices to improve the quality of care more generally will yield better long-term results. Fortunately, there are signs within the safety movement that this shift is already under way — a change that promises a more productive next five years. Traditionally, research into quality of care has focused on three areas: variation, patient-centered care, and compliance with guidelines.6-9 The IOM report added the domain of safety to quality research. Researchers linked insights into causation from cognitive psychology, human-factors engineering, and systems science with existing data on the incidence of iatrogenic injury10 — data drawn from studies in the 1990s that were oriented toward understanding medical malpractice, rather than improving health care.11 The product was the concept of “preventable injury,” whose burden became the cornerstone of the IOM report. Patient safety sparked a level of public interest that the rest of the quality-improvement field in health care had failed to excite. This was due, at least in part, to the ability of the patient-safety movement to harness a public fascination with the accidental death — an individual patient sustaining preventable harm from an error of either omission or commission. This notion prompted the popular analogy to an airline crash. When a plane goes down, investigators count the victims and then try to figure out what caused the crash and how it could have been avoided. The IOM estimated there were 44,000 to 98,000 preventable hospital deaths per year, and the public could easily make the leap from a press report about a death, such as the chemotherapy overdose of medical reporter Betsy Lehman at the Dana– Farber Cancer Institute in Boston, to this alarming statistic. By contrast, the other dimensions of quality improvement track changes in populations over time. Increments and decrements are measured in “statistical lives” — better outcomes across populations resulting from the consistent and appropriate provision of effective interventions, such as the administration of beta-blockers and statins and the performance of such procedures as aortic aneurysm the premise and promise of safety