US police killings undercounted by half, study using Guardian data finds
Harvard study finds over half of deaths wrongly classified, in latest example of databases greatly undercounting police killings
Over half of all police killings in 2015 were wrongly classified as not having been the result of interactions with officers, a new Harvard study based on Guardian data has found.
The finding is just the latest to show government databases seriously undercounting the number of people killed by police.
Right now the data quality is bad and unacceptable, said lead researcher Justin Feldman. To effectively address the problem of law enforcement-related deaths, the public needs better data about who is being killed, where, and under what circumstances.
Feldman used data from the Guardians 2015 investigation into police killings, The Counted, and compared it with data from the National Vital Statistics System (NVSS). That dataset, which is kept by the Centers for Disease Control and Prevention (CDC), was found to have misclassified 55.2% of all police killings, with the errors occurring disproportionately in low-income jurisdictions.
As with any public health outcome or exposure, the only way to understand the magnitude of the problem, and whether it is getting better or worse, requires that data be uniformly, validly, and reliably obtained throughout the US, said Nancy Krieger, professor of social epidemiology at Harvards Chan School of Public Health and senior author of the study. Our results show our country is falling short of accurately monitoring deaths due to law enforcement and work is needed to remedy this problem.