Primary Outcomes (explanation)
To assess effects on outcomes in the field, we use CPD's administrative data. Specifically, we use data from Tactical Response Reports (TRRs) to measure uses of force. TRRs provide comprehensive information on force incidents since they must be filled out every time a subject resists an officer, is injured by an officer, threatens an officer, or physically attacks an officer (Chicago Police Department, 2021).
In the post-training data we analyze, uses of force are divided into 3 categories: Level 3 comprises lethal uses of force (e.g., police shootings); while Levels 1 and 2 comprise all non-lethal uses of force (which range from using a TASER, using a wristlock, or punching and kicking). We distinguish between lethal and non-lethal levels of force (per our pre-analysis plan) since there are only 20 lethal force incidents in our sample, and we are not powered to detect changes in this outcome. We therefore focus on non-lethal uses of force, and our main measure is the number of such incidents associated with each officer.
The TRRs contain other information on subject injury and tactics, which we use to construct additional measures analyzed in Table B13. These include: officer recorded injuries, subject allegations of injuries, measures of hospitalization, and an index of officer reliance on force tactics (versus other types of tactics) in use of force incidents.
We also draw on CPD's arrest data to examine various types of arrests. We pre-specified examining a set of arrests categorized as discretionary, for charges such as disorderly conduct and resisting or obstructing an officer. These charges often arise in situations where officers can either choose to make an arrest or resolve the situation in other ways. Therefore, these discretionary arrests are often perceived to be arbitrary or unnecessary, while holding little public safety value. As such, the number of discretionary arrests is one of our main measures of adverse policing outcomes.
To gauge effects on officer activities more generally, we turn to administrative data from the Performance Recognition System (PRS), and we use it to build an index of officer activity which includes: warrants; recovered vehicles; recovered guns; traffic stops; driver stops; Investigatory Stop Reports (ISRs)/contact cards; Administrative Notices of Ordinance Violation (ANOVs); citations; curfew violations; CTA checks; parking citations; and all other non-discretionary arrests. To measure effects on officer injuries, we use daily attendance data, which provides information on days off due to injury on duty (IOD).