A better surveillance system for tracking police homicides

Official counts of homicides by police seriously undercount incidents, according to a study from Harvard T.H. Chan School of Public Health, but a relatively new national data system, currently in use in 32 states, could be a crucial tool for gathering more comprehensive information, say the researchers.

The study, which was published online March 17, 2016 in the American Journal of Public Health, found that the U.S. Centers for Disease Control and Prevention’s National Violent Death Reporting System (NVDRS) provided more complete and accurate data on police homicides compared with two other national data systems.

“The U.S. is trying to get a handle on police homicides, but how do we learn which policies best prevent these deaths and protect police if we can’t even get an accurate count of them?” said Catherine Barber of the Harvard Injury Control Research Center (HICRC) at Harvard Chan School. “The NVDRS could be the best solution to this vexing problem.”

Counts of homicides by police are currently tracked by two official national data sources: the CDC’s National Vital Statistics System and Supplementary Homicide Reports (SHRs) from the FBI’s Uniform Crime Reports System. But these data sources each rely on a single source—death certificates for the CDC’s system and voluntary police reporting for the FBI’s system—and the study suggests that each undercounts police homicides by as much as half. In addition, the extent of undercounting varies greatly by state, making comparisons among states and municipalities unreliable.