The authors found that inside medical institutions, fatal medication errors spiked in July and in no other month. This July peak was visible only in counties with teaching hospitals. In these counties, the number of July deaths from medication errors was 10 percent above the expected level. No similar link was observed for other causes of death or for deaths outside hospitals.
According to sociology professor David Phillips and his student Gwendolyn Barker from the University of California, San Diego, fatal medication errors peak in July in counties with teaching hospitals, which coincides with the yearly influx of new medical residents who are given increased responsibility for patient care.