Criminal justice systems are tasked with responding to a wide range of activities deemed to be illegal and against public interest. Subtle distinctions in offense descriptions reflect deep differences in offense severity, potential motive, risk to public safety, and optimal responses by law enforcement. Accurately classifying offenses helps us to better understand the nature of crime, allow policy makers to evaluate the effectiveness of criminal justice policies, and provide the research community and the public a common measurement system to effectively analyze crime trends over time and across jurisdictions. Organizing and classifying criminal activity is a core premise of well-functioning system of criminal justice.
Prior schema efforts have been inadequate due to their exclusive focus on felony-level offenses, lack of internal consistency, or lack of specificity on emerging crime types (e.g. possession of methamphetamine or possession of heroin versus possession of illegal drugs). As of January 2021, the Federal Bureau of Investigation (FBI) officially adopted the National Incident-Based Reporting System (NIBRS) for consolidating arrest data and provides information on 46 different classifications and 53 other contextual elements such as victim information. Although the NIBRS aims to provide more information in regards to the specific circumstances and context of a crime, one of the key challenges for researchers and public users is the complexity of the data collection system which has led to slow adoption rate by law enforcement agencies. In addition, NIBRS users must have the technical knowledge to aggregate the incident-level data as well as have the necessary understanding of the NIBRS data infrastructure to design their own sub-classification of offense types for their analysis. Lastly, offense crosswalks for NIBRS charge codes are not available to the general public.
In contrast, the National Corrections Reporting Program (NCRP) produced by the Bureau of Justice Statistics (BJS) collects offender-level data on prison and supervision admissions and releases. Although the publicly available offense crosswalks make NCRP convenient for analyzing crime data, there remain limitations. Foremost, the NCRP offense crosswalks do not provide significant information for the multitude of misdemeanor and low level offense types since the data collection itself is focused on prison and post-confinement records. A more concerning issue is that the NCRP offense codes may not always be consistent for a given offense description. In the 2020 version, the description “MANSLAUGHTER” is associated with 3 different charge codes for “Homicide,” “Voluntary Manslaughter,” and “Manslaughter.” In effect, users without all of the identifying variables such as the statute code of the offense description will have to rely on subjective deduplication for consistent offense classification in their data.
Uniform Crime Classification Standard
In order to address the shortcomings of prior schemas, we created the Uniform Crime Classification Standard (UCCS). It is grounded in the original offense type delineations developed for the NCRP in the early 1990s, but with modifications including reordering offenses to reflect their seriousness, adding clarifications to the NCRP codes to ensure coding consistency, reclassifying DUI to its own offense type, reclassifying many of the “other” and “public order” offenses to more specific definitions, and adding new codes for previously omitted offenses including human trafficking, amphetamine drug offenses, opiate drug offenses, and other prescription drug offenses.
UCCS is operationalized as a four digit offense code that is hierarchical in nature. The first digit represents the broad crime type, which can take on values: 1-Violent, 2-Property, 3-Drug Offense, 4-DUI, 5-Public Order, or 6-Criminal Traffic. For each broad crime type, offense category codes are generated by enumerating from 01 to 99 where 99 is reserved for “Other” category within the broad crime type (e.g. if broad crime type code is 1, then 99 maps to “Other Violent Offense”). The final digit is reserved as an offense modifier used to delineate whether: 0-an offense was committed, 1-an offense was attempted, or 2-an offense was conspired.
|1||1021||Unspecified Homicide, Attempt|
|2||1022||Unspecified Homicide, Conspiracy|
|0||1990||Other Violent Offense|
|1||1991||Other Violent Offense, Attempt|
|2||1992||Other Violent Offense, Conspiracy|