re: The Confluence of Events Leading to O's Downfall

A primary obstacle to the study of police use of force has been the lack of readily available data.
Data on lower level uses of force, which happen more frequently than officer-involved shootings, are
virtually non-existent. This is due, in part, to the fact that most police precincts don’t explicitly
collect data on use of force, and in part, to the fact that even when the data is hidden in plain
view within police narrative accounts of interactions with civilians, it is exceedingly difficult to
extract.

From the same study.