← counting-cars-plates
Source
FBI Crime Data Explorer — Return A master file (offenses known and clearances by arrest, agency-level) + Law Enforcement Employees agency crosswalk
https://cde.ucr.cjis.gov/
retrieved 2026-08-17
Method
sum(violent_cleared) / sum(violent_actual) over 12-month-reporting agencies in top-quartile-density counties
from: data/county-camera-clearance-join.json
Caveats
- Underlying camera locations are volunteer-crowdsourced (DeFlock/OSM), not verified by any camera operator or government body -- likely incomplete, possibly outdated or inaccurate (see repo TERMS.md).
- County aggregates cover only agencies with a resolved county FIPS that reported all 12 months of the year to the FBI (Return A master file); state/federal and multi-county agencies are excluded. Camera-dense counties skew urban with structurally different caseloads/clearance baselines regardless of camera presence, and a given year's clearances are not necessarily for offenses reported that year. Correlation, not causation.
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