June 11 1930, through IACP lobbying, the United States Congress passed legislation enacting 28 USC §534, which granting the office of the Attorney General the ability to “acquire, collect, classify, and preserve identification, criminal identification, crime, and other records” with the ability appoint officials to oversee this duty, including the subordinate members of the Bureau of Investigation. In 1930, full authority was passed to the Bureau of Investigation, which was renamed numerous times throughout the 1930’s eventually becoming the Federal Bureau of Investigation in 1935, the July 1930 issue of the IACP crime report serving as notice of the FBI’s takeover of the program. While the IACP discontinued oversight of the program, they continued to advise the FBI to better the UCR.
Since 1935, the FBI served as a data clearinghouse; organizing, collecting, and disseminating information voluntarily submitted by local, state, federal and tribal law enforcement agencies. The UCR remained the primary tool for collection and analysis of data for the next half century. Throughout the 1980s, a series of National UCR Conferences were with members from the IACP, Department of Justice, including the FBI, and newly formed Bureau of Justice Statistics (BJS). The purpose was to determine necessary system revisions and then implement them. The result of these conferences was the release of a “Blueprint for the Future of the Uniform Crime Reporting Program” release in May 1985, detailing the necessary revisions. The report proposed splitting reported data into two separate categories, the eight ‘serious’ crimes and twenty-one less commonly reported crimes. The eight serious crimes became known as Part I index crimes. The additional twenty-one crimes are considered Part II index crimes.
In 2003, FBI UCR data were compiled from more than 16,000 agencies, representing 93 percent of the population in forty seven states. While nationally reporting is not mandated, many states have instituted laws requiring law enforcement within those states to provide UCR data. The continued growth an improvement of the UCR is unlikely as the US Department of Justice and other UCR Conference members have decided to integrate the UCR program into the NIBRS program, created in the late 1980s based on the UCR framework.
For reporting purposes, criminal offenses are divided into two major groups: Part I offenses and Part II offenses.
In Part I, the UCR indexes reported incidents in two categories: violent and property crimes. Aggravated assault, forcible rape, murder, and robbery are classified as violent while arson, burglary, larceny-theft, and motor vehicle theft are classified as property crimes. These are reported via the document named Return A - Monthly Return of Offenses Known to the Police. Part 1 crimes are collectively known as Index crimes, this name is used because the crimes are considered quite serious, tend to be reported more reliably than others, and are reported directly to the police and not to a separate agency (ex- IRS) that doesn't necessarily contribute to the UCR.
In Part II, the following categories are tracked: simple assault, curfew offenses and loitering, embezzlement, forgery and counterfeiting, disorderly conduct, driving under the influence, drug offenses, fraud, gambling, liquor offenses, offenses against the family, prostitution, public drunkenness, runaways, sex offenses, stolen property, vandalism, vagrancy, and weapons offenses.
Two property reports are also included with the Return A. The first is the Property Stolen by Classification report. This report details the number of actual crimes of each type in the Return A and the monetary value of property stolen in conjunction with that crime. Some offenses are reported in greater detail on this report than on the Return A. For example, on the Report A, burglaries are divided into three categories: Forcible Entry, Unlawful Entry - No Force, and Attempted Forcible Entry. On the Property Stolen by Classification report, burglaries are divided into six categories based on location type and the time of the offense. Offenses are counted in residences with offense times of 6pm to 6am, 6am to 6pm and Unknown Time and Non-residences with the same three time groupings.
The second property report is the Property Stolen by Type and Value report. The monetary value of both stolen and recovered property are totaled and classified as one of eleven property types:
The FBI began recording arson rates, as part of the UCR, in 1979. This report details arsons of the following property types:
The UCR does not include simple assaults in part 1 and minor assaults, verbal assaults and other such crimes, which can account for between 50% and 90% of violent crimes in other countries, are not recorded.