OBJECTIVES:

This study assessed the consistency of estimates of the number of justifiable homicides committed by US police officers and identified sources of underreporting.

METHODS:

The number of justifiable homicides committed by police officers between 1976 and 1998 was estimated from supplementary homicide report (SHR) and National Vital Statistics System (NVSS) mortality data.

RESULTS:

Nationally, the SHR estimate was 29% larger than the NVSS estimate. However, in most states this pattern was reversed, with more deaths reported in the NVSS.

CONCLUSIONS:

Both systems underreport, but for different reasons. The NVSS misclassifies cases as homicides, rather than justifiable homicides committed by police officers, because certifiers fail to mention police involvement. The SHR misses cases because some jurisdictions fail to file reports or omit justifiable homicides committed by police officers.