The study and practice of patient safety has seen a surge over the last 10 years. New resident training and staffing policies, health information technologies, error reporting systems, team models of care, training methods, patient involvement, information handoff strategies, just cultures, and many other interventions have been mandated or attempted to improve the safety of patient care. While some of these interventions focus on individual providers and others focus on organization-level changes, little, if any, patient safety research has purposefully sought to understand how variables at different levels, such as the provider level or organization level, interact to impact patient safety outcomes such as errors, adverse drug events, or patient harm. Looking at relationships across levels is important because adverse events might be related to variables at different levels; consider that adverse events may be nested within patients, patients nested within nurses and physicians, nurses and physicians nested within shifts, shifts nested within hospital units, and so forth. Because these nested levels exist, they may exert as yet untested influence on the levels below. In this paper the impact of levels on theory, measurement, analysis and intervention in patient safety research is discussed.
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