What You'll Learn
The Concept
Students frequently hear statements such as: 'Crime increased.' 'Violent crime decreased.' 'Robbery is rising.' Before accepting any crime statistic, a criminal-justice student should ask: Where did the data come from?
One of America's primary sources of police-reported crime information is the FBI's Uniform Crime Reporting Program, commonly called UCR. For decades, much national crime reporting relied heavily on the Summary Reporting System. The FBI subsequently transitioned toward the more detailed National Incident-Based Reporting System, or NIBRS.
NIBRS collects much more information about individual criminal incidents, including details concerning offenses, victims, known offenders, arrestees, relationships, and property involved. Consider a single incident involving a burglary, assault, theft, and weapon offense. An incident-based system can preserve considerably more information about what actually occurred than a simplified counting system.
Crime Statistics Have Limitations: Police data only reflect crimes that become known to law enforcement and are recorded within reporting systems. Many crimes are never reported. Others may be classified differently based upon legal definitions or reporting rules. Agency participation and data quality can also influence national statistics. For this reason, researchers frequently compare police-reported data with additional information such as victimization surveys.
Better crime data allows agencies to analyze victim characteristics, offender characteristics, relationships, locations, weapons, time patterns, multiple offenses, and geographic patterns. These data can support crime analysis, resource allocation, research, prevention strategies, and public policy.
The FBI also provides the Crime Data Explorer, allowing researchers, students, journalists, and the public to examine national crime information.
Real-World Application
A news headline reads: 'Violent crime in [City] increased 15% last year.' A critical reader asks: What crimes are included in 'violent crime'? Did the city change its reporting practices? Did agency participation in the reporting system change? Was this a single-year fluctuation or part of a trend? How does this compare to victimization survey data? What is the baseline — 15% of what number? Answering these questions transforms a headline into an informed analysis.
Why It Matters
For Police Officers
Officers and crime analysts who understand UCR and NIBRS can use crime data more effectively for deployment decisions, problem-solving initiatives, and grant applications. Understanding data limitations also helps officers respond accurately when community members cite crime statistics.
For Students
Crime statistics appear in virtually every criminal-justice research paper, policy debate, and news story. Students who understand how crime is measured — and what the limitations are — can evaluate those statistics critically rather than accepting them at face value.
Think About It
Why might crime statistics decrease even if the actual number of crimes occurring in a community stays the same or increases?
How does NIBRS improve upon the traditional UCR Summary Reporting System? What types of analysis does it enable that were not previously possible?
Why do researchers use victimization surveys alongside police-reported data rather than relying on one source alone?
Sources & Further Reading
Federal Bureau of Investigation. Crime Data Explorer. cde.ucr.cjis.gov.
Bureau of Justice Statistics. National Crime Victimization Survey. bjs.gov.
Federal Bureau of Investigation. National Incident-Based Reporting System. ucr.fbi.gov.