Coverage & caveats · FBI crime statistics
The 2021 NIBRS transition
The break in the national crime series caused by retiring summary reporting — the single biggest trap in FBI data.
When the FBI retired the Summary Reporting System at the start of 2021, agencies that had not yet converted to NIBRS simply stopped appearing in the national data. Coverage collapsed: agencies representing a large share of the U.S. population, including some of the biggest city departments, are missing from 2021 entirely, and the recovery since has been gradual and uneven.
This produces the most common false finding in American crime reporting: comparing 2020 to 2021 and concluding that crime fell steeply, when much of the fall is departments that stopped reporting. Any trend crossing 2021 must account for which agencies were present in each year. The FBI publishes its own estimates that attempt to bridge the gap; those estimates are a reconstruction, not a count, and should be labelled as such.
Also known as: NIBRS transition, 2021 crime data gap, crime data break.
See the 2021 nibrs transition in the data
Explore reported offences and trends by state and county, with the coverage caveats stated on every page. Start free — no credit card needed.
The 2021 NIBRS transition — FAQ
What is the 2021 nibrs transition in crime statistics?+
The break in the national crime series caused by retiring summary reporting — the single biggest trap in FBI data. When the FBI retired the Summary Reporting System at the start of 2021, agencies that had not yet converted to NIBRS simply stopped appearing in the national data. Coverage collapsed: agencies representing a large share of the U.S. population, including some of the biggest city departments, are missing from 2021 entirely, and the recovery since has been gradual and uneven.
Why does the 2021 nibrs transition matter?+
This produces the most common false finding in American crime reporting: comparing 2020 to 2021 and concluding that crime fell steeply, when much of the fall is departments that stopped reporting. Any trend crossing 2021 must account for which agencies were present in each year. The FBI publishes its own estimates that attempt to bridge the gap; those estimates are a reconstruction, not a count, and should be labelled as such.
Where does this crime statistics come from?+
Figures come from the FBI's Uniform Crime Reporting program — the quarterly national trend series, the National Incident-Based Reporting System (NIBRS), and the annual Arrests and Arson collections. Coverage depends on which agencies reported in a given period. pumsdata is independent and not affiliated with the FBI.