Lag time in an incident reporting system at a university hospital in Japan.

Background: Delays and underreporting limit the success of hospital incident reporting systems, but little is known about the causes or implications of delayed reporting.
Setting and Methods: The authors examined 6880 incident reports filed by physicians and nurses for three years at a national university hospital in Japan and evaluated the lag time between each incident and the submission of a report.
Results: Although physicians and nurses reported nearly equal numbers of events resulting in major injury (32 v 31), physicians reported far fewer minor incidents (430 v 6387) and far fewer incidents overall (462 v 6418). In univariate analyses, lag time was significantly longer for physicians than nurses (3.79 v 2.20 days; p<0.001). In multivariate analysis, physicians had adjusted reporting lag time 75% longer than nurses (p<0.001) and lag time for major injuries was 18% shorter than for minor injuries (p = 0.011). Adjusted lag time in 2002 and 2004 were 34% longer than in 2003 (p<0.001).
Conclusions: Physicians report fewer incidents than nurses and take longer to report them. Quantitative evaluation of lag time may facilitate improvements in incident reporting systems by distinguishing institutional obstacles to physician reporting from physicians' lesser willingness to report.