While this will not surprise anyone familiar with the state of police accountability in the United States, a new study reports that over half of killings by police have been mislabeled over the past 40 years. As also would be expected from anyone familiar with American policing, black men are killed and their deaths mislabeled at disproportionally high rates. One easy and obvious objection to the claims made in the study is to point out the federal government does not have a comprehensive system of tracking police caused deaths or use of force. As such, no one can claim to know the actual numbers.
On the one hand, that is a reasonable criticism. While journalists and academics have been tracking police deaths and use of force, this is a piecemeal effort that depends on the ability of individual journalists and researchers to gather and confirm information. While the National-Use-of-Force Data Collection lunched in 2019, most police departments simply decline to provide data.  As such, we cannot claim to know the exact number of police caused deaths nor the exact percentage that have been mislabeled. We cannot also claim to know the exact number of police uses of force and what percentage of these were not justified.
That said, the authors of the study are using the best available data from the National Vital Statistics System, Fatal Encounters, Mapping Police Violence, and the Guardian’s The Counted. This data, while incomplete, does provide what seems to be the foundation for a reasonable inductive generalization from the sample to the whole. Naturally, we need to keep in mind the usual concerns about sample size and the possibility of a biased sample. But one cannot simply assert that the sample must be too small or biased; one would need to support these claims.
On the other hand, this criticism (perhaps ironically) just points to a huge problem: we do not have accurate and complete data on police killings and use of force. While one could claim that the missing. . .