Crime rate

The crime rate measures how much crime occurs in a given area or period, standardized by population so places of different sizes can be compared, most commonly expressed as incidents per 100,000 residents per year.

The basic formula is crime rate = (reported incidents / population) × 100,000, calculated separately for different offense categories, violent crime and property crime in particular, since a single combined rate can hide very different trends underneath. Crime rates are built from administrative data such as police incident reports, which record crimes that were reported to and recorded by police, not necessarily all crimes that actually occurred; victimization surveys are a separate, complementary source meant to capture the unreported crime that police data misses. Rates calculated at fine geography, such as census tract or patrol-beat level, are the basis for hotspot analysis.

Crime rate trends drive policing resource allocation, political debate, and public perceptions of safety, but the statistic is sensitive to definitional and reporting changes: shifts in how an offense is classified, changes in how willing victims are to report a crime, especially chronically underreported ones such as sexual assault or domestic violence, and changes in police recording practices can all move the rate without any real change in underlying crime. Comparing rates across jurisdictions also requires care, since legal definitions of offenses, and how consistently records are linked across systems via record linkage, vary by place.