Interruptions in Health Care: Assessing Their Connection With Error and Patient Harm.

OBJECTIVE: We address the problem of how researchers investigate the actual or potential causal connection between interruptions and medical errors, and whether interventions might reduce the potential for harm. BACKGROUND: It is widely assumed that interruptions lead to errors and patient harm. However, many reviewers and authors have commented that there is not strong evidence for a causal connection. METHOD: We introduce a framework of criteria for assessing how strongly evidence implies causality: the so-called Bradford Hill criteria. We then examine four key "metanarratives" of research into interruptions in health care-applied cognitive psychology, epidemiology, quality improvement, and cognitive systems engineering-and assess how each tradition has addressed the causal connection between interruptions and error. RESULTS: Outcomes of applying the Bradford Hill criteria are that the applied cognitive psychology and epidemiology metanarratives address the causal connection relatively directly, whereas the quality improvement metanarrative merely assumes causality, and the cognitive systems engineering metanarrative either implicitly or explicitly questions the feasibility of finding a direct causal connection with harm. CONCLUSION: The Bradford Hill criteria are useful for evaluating the existing literature on the relationship between interruptions in health care, clinical errors, and the potential for patient harm. In the future, more attention is needed to the issue of why interruptions usually do not lead to harm, and the implications for how we approach patient safety.