Data Methodology

Primary Data Source

All crime data on PlainCrime is sourced from the FBI's Uniform Crime Reporting (UCR) program — the nation's most comprehensive standardized crime data collection. Specifically:

  • Table 8 — Offenses Known to Law Enforcement by State by City
  • Table 10 — Offenses Known to Law Enforcement by State by Metropolitan and Nonmetropolitan Counties
  • FBI Crime Data Explorer (CDE) API — State-level crime trends

Data Vintage

PlainCrime uses the most recently available FBI UCR annual release. UCR data is published approximately 1 year after the reporting period. The database reflects city-level crime data for 8,986 jurisdictions across the United States. UCR data represents the most comprehensive standardized crime statistics available at the city level, though participation rates vary by state and year. Some states have nearly complete agency participation, while others have significant gaps.

Processing Pipeline

  1. FBI UCR Table 8 and Table 10 CSV files are downloaded from the FBI's public data portal.
  2. City-level offense totals for violent crime (murder, rape, robbery, aggravated assault) and property crime (burglary, larceny-theft, motor vehicle theft, arson) are extracted.
  3. Per-capita crime rates are computed using FBI-reported population figures: Rate = (Offenses ÷ Population) × 100,000.
  4. Safety grades are calculated by comparing each jurisdiction's crime rate against national UCR averages for cities of similar size. The size-adjusted comparison is critical because crime rates naturally correlate with population density and urbanization — comparing a small rural town directly against a major metropolitan area would produce misleading results. Our grading methodology groups jurisdictions into population tiers and evaluates each city against its peers.
  5. State-level trend data is pulled from the FBI Crime Data Explorer API and joined to state records.
  6. All data is loaded into a structured SQLite database serving city, county, and state pages.

Crime Categories

The FBI Uniform Crime Reporting program categorizes offenses into two broad groups. Violent crimes involve the use or threat of force against a person. Property crimes involve the taking or destruction of property without force or threat against a person.

Violent Crime

  • Murder and nonnegligent manslaughter
  • Rape
  • Robbery
  • Aggravated assault

Property Crime

  • Burglary
  • Larceny-theft
  • Motor vehicle theft
  • Arson

How the Source Agency Collects Data

The FBI Uniform Crime Reporting program collects crime data from approximately 18,000 city, county, university, state, tribal, and federal law enforcement agencies across the United States. Participation is voluntary — agencies submit monthly returns reporting the number of offenses known to law enforcement in their jurisdiction. The FBI standardizes crime definitions across agencies using the UCR Summary Reporting System classification rules so that crimes reported in different states follow the same counting methodology.

State-level UCR programs serve as intermediaries, collecting data from local agencies within each state and forwarding it to the FBI. The FBI reviews submissions for accuracy, contacts agencies about anomalies, and publishes the compiled data in the annual Crime in the United States report.

Data Accuracy Commitment

PlainCrime presents FBI UCR data without modification. Crime counts, per-capita rates, and safety grades are computed directly from the published UCR tables. We do not estimate crime for non-reporting agencies or adjust figures for underreporting. If you find any data that appears incorrect, please contact us at hello@plaincrime.com and we will verify against the FBI source data.

Limitations

  • UCR participation is voluntary — not all law enforcement agencies submit data every year. Missing data does not mean zero crime.
  • Reporting practices, crime definitions, and local factors vary across jurisdictions, making direct city-to-city comparisons imperfect.
  • Population figures used for rate calculations come from FBI-reported populations, which may differ from Census estimates.
  • Crime statistics should not be used as the sole basis for decisions about personal safety or relocation.
  • PlainCrime is not affiliated with the FBI or any government agency.