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GlossaryStatistics and interpretation

Arrest rate

An arrest rate relates arrest events to a stated population and scale. Learn why it is different from conviction, clearance, or individual risk.

An arrest rate is the number of qualifying arrests divided by a specified population, usually expressed using a scale such as arrests per 100,000 people. The rate measures recorded enforcement actions relative to that denominator. It does not measure the percentage of crimes solved or the percentage of residents convicted.

Define both sides of the calculation

A common calculation is arrests ÷ population × 100,000. The publication must establish which arrests and population are included. Rates for an age group require an appropriate age-group denominator, while an overall resident rate uses a different population basis.

The FBI explains that UCR arrest figures count separate occasions when people are arrested, cited, or summoned under program rules. Repeated arrests of the same person can appear more than once. These figures therefore do not represent unique people arrested. FBI arrest definition

Some national arrest products are estimated rather than simple sums. The FBI's 2019 table methodology, for example, used complete-year reporters to develop national estimates. That is a historical example, not a claim that every current arrest product uses the same procedure. FBI 2019 methodology

Example

Hypothetical example: An agency records 300 qualifying arrest events in a year for a jurisdiction with a matching population denominator of 50,000. The rate is 600 arrests per 100,000 people.

The count remains 300. If some people were arrested on more than one occasion, fewer than 300 distinct people may be represented. Some arrestees may also live elsewhere, so the rate cannot be read as the probability that a resident was arrested.

Common confusion

An arrest rate is different from a clearance rate, which relates qualifying clearances to the relevant offense measure under program rules. It is also different from a conviction rate, which concerns court outcomes and needs its own numerator and denominator.

Dividing arrests by recorded offenses produces another ratio, not the same population-based arrest rate. Arrests can occur long after an offense and do not necessarily correspond one-for-one with offense records in the same period.

Interpreting differences

Higher arrest rates can reflect differences in recorded conduct, enforcement activity, law, population exposure, and reporting. The rate alone cannot establish the cause or demonstrate policing quality. Check offense group, age coverage, agency participation, and treatment of citations before comparing places or years. Describe the rate's actual unit so the comparison remains clear.

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