How the prototype dataset is built

Sources

Crime data comes from FBI NIBRS state bulk files provided as official source archives. Population context uses Census Vintage 2025 subcounty estimates for the matching data year where available.

Dataset use notice

The structured dataset pages are free to access. The underlying FBI and Census inputs are public U.S. government source data; Area Safety Data adds matching, filtering, explanatory text, and page-level presentation. For official analysis, cite and verify against the original FBI and Census sources.

Selected offense definition

The current property-crime definition uses NIBRS codes 200, 220, 240, and 23A through 23H: arson, burglary/breaking and entering, motor vehicle theft, and larceny/theft offenses.

Publication gates

A city page must have a publishable city-type FBI agency, NIBRS participation, a unique Census match, non-covered agency status, positive offense counts, and a minimum Census 2024 population of 5,000 for automatic indexation.

Small towns

Small places remain in the review queue. They can be valuable for search, but they should be handled as noindex drafts, county/state rollups, or manually reviewed pages until the match quality and denominator risk are clear.

Trends

The pipeline supports multiple FBI years. A trend is only shown when at least two validated years exist for the same city; otherwise the page explicitly says that trend data is pending.