Despite mandates for US hospitals to maintain incident reporting systems, little is known about the utility of the data collected. This study linked incident report and discharge databases at two hospitals to examine how frequently reports were filed and what types of incidents were documented. The vast majority of reports were filed by nurses, with less than 2% filed by physicians (a problem noted in prior research). This pattern likely influenced the spectrum of problems reported; only a small proportion of reported incidents related to procedures. A prior commentary proposed a theoretical framework for using incident reporting data to improve safety.