GlossaryCrime reporting systems
Part I offense
A Part I offense is an offense in the major-crime grouping used by the FBI's historical Summary Reporting System (SRS).
A Part I offense is an offense in the major-crime grouping used by the FBI's historical Summary Reporting System (SRS). The grouping supported reporting of offenses known to law enforcement as well as arrests. It belongs to a particular statistical framework and is not a synonym for every serious crime or felony.
What the grouping contains
The FBI's 2018 offense definitions organize Part I around criminal homicide, rape, robbery, aggravated assault, burglary, larceny-theft, motor vehicle theft, and arson, with specific definitions and reporting treatment. The heading therefore identifies a reporting structure, not a complete inventory of harmful conduct.
Older annual reports and long-term local dashboards can still use these labels. Read a Part I total with its underlying categories and footnotes, particularly when the table distinguishes violent crime, property crime, or an index total. A narrower subtotal may not include everything shown under the broader heading.
Example
Hypothetical example: A city report presents ten years of “Part I offenses” and a newer table of NIBRS Group A offenses. The newer table includes categories not present in the Part I series.
The two totals cannot be joined into one continuous measure just because both concern police-recorded offenses. A comparison needs a documented selection of matching categories and compatible counting rules. The newer total could be larger partly because it covers more types of conduct.
Common confusion
Part I is not the same grouping as NIBRS Group A. Similarly, “Part I” does not mean “felony”: felony is a legal classification under the relevant law.
Part II also does not mean that every included matter is minor. It is another reporting grouping with a different collection basis.
Historical scope
Use the reporting instructions applicable to the year and table. If an agency retains Part I terminology in a modern dashboard, its methodology should explain whether it is publishing original SRS data or a reconstruction from incident-based records. That distinction affects comparisons and what the totals represent.