Context: A major purpose of incident reporting is to understand contributing factors so that causes of errors can be uncovered and systems made safer. For established reporting systems in US hospitals, little is known about how well the reports identify contributing factors.
Objective: To characterise the information incident report narratives provide about contributing factors using a taxonomy we developed for this purpose.
Design: Descriptive study examining 2228 reports for 16 575 randomly selected patients discharged from an academic and a community hospital in the US between 1 January and 31 December 2001.
Main outcomes measured: Reports in which patient, system and provider (errors, mistakes and violations) factors were identifiable.
Results: 80% of reports described at least one contributing factor. Patient factors were identifiable in 32%, most frequently illness (61% of these reports) and behaviour (24%). System factors were identifiable in 32%, most commonly equipment malfunction or difficulty of use (38%), problems coordinating care among providers (31%), provider unavailability (24%) and tasks that were difficult to execute correctly (20%). Provider factors were evident in 46%, but half of these reports contained insufficient detail to determine which specific factor. When detail sufficed, slips (52%), exceptional violations (22%), lapses (15%) and applying incorrect rules (13%) were common.
Conclusions: Contributing factors could be identified in most incident-report narratives from these hospitals. However, each category of factors was present in a minority of reports, and provider factors were often insufficently elucidated. Greater detail about contributing factors would make incident reports more useful for improving patient safety.