The National Vital Statistics System (NVSS) is supposed to keep track of how Americans die. It’s an important tool for assessing trends in disease, behavior and public safety, both currently and for historians. But NVSS gets its data from other government agencies, which in some cases get them from others. Perhaps it shouldn’t be surprising, but when it comes to tracking deaths caused by government — in this case, people killed by law enforcement officers — government agencies are doing a pretty lousy job. The Guardian reports:

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 Guardian’s 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.

I suspect this is largely because the NVSS has been using FBI data on police killings, and thanks to the databases kept by the Guardian and The Washington Post, we now know that the FBI figure has been off by about 50 percent or so. That’s because despite the fact that police agencies were required to report the number of times their officers killed someone, there was no enforcement mechanism, so many didn’t bother. This rendered the data essentially useless. We’ll know more about trends in this area once the Post and Guardian databases are up and running for several years. The FBI has made some changes, but we won’t really know how effective they are until we can compare them to the media lists. In the meantime, for all the talk of “fake news,” it’s interesting to point out that if the NVSS really wants to provide an accurate record of how Americans die, it’s better off relying on the work of two newspapers than on the work of the FBI.