Police Performance Rankings Depend on the Functional Form of the Index

Bearfield, Maranto and Wolf (2020) advise policy-makers to measure policing outcomes using a metric that includes rates of homicide, police-related civilian deaths (PRCD) , and poverty. They present such an index, which they call the Police Performance Index (PPI). But alternative functional forms that are equally plausible can lead to different rankings of police departments, and therefore different policy conclusions. My comment presents one such alternative index, under which changes in police-related civilian deaths have a greater potential effect on a city’s ranking: https://doi.org/10.31235/osf.io/r8yst