Some instruments administered as part of this study may contain in whole or substantially in part contents from copyrighted instruments. Reproductions of the instruments are provided as documentation for the analysis of the data associated with this collection. Restrictions on "fair use" apply to all copyrighted content. More information about the reproduction of copyrighted works by educators and librarians is available from the United States Copyright Office.

The copyright law of the United States (Title 17, United States Code) governs the making of photocopies or other reproductions of copyrighted material. Under certain conditions specified in the law, libraries and archives are authorized to furnish a photocopy or other reproduction. One of these specified conditions is that the photocopy or reproduction is not to be "used for any purpose other than private study, scholarship, or research." If a user makes a request for, or later uses, a photocopy or reproduction for purposes in excess of "fair use," that user may be liable for copyright infringement.

The UNIFORM CRIME REPORTING PROGRAM DATA: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2010 reports counts of arrests and offenses for the Uniform Crime Reports (UCR) index (Part I) crimes: murder, rape, robbery, aggravated assault, burglary, larceny, auto theft, and arson. The UCR County-level Arrest files also report arrests for additional (Part II) crimes such as forgery, fraud, vice offenses, and drug possession or sale. The data were originally collected by the Federal Bureau of Investigation (FBI) from reports submitted by agencies and states participating in the UCR Program. Each agency or jurisdiction is uniquely identified in the collection by the UCR Originating Agency Identifier (ORI). In describing this data collection the terms agency, jurisdiction, and ORI are used synonymously. Detailed discussions of reporting procedures are found in the UNIFORM CRIME REPORTING HANDBOOK (Washington, DC: U.S. Government Printing Office, 1980), and in the codebooks for the ICPSR's Agency-level UCR data collections (see ICPSR 9028). It should be emphasized that, while UCR staff were consulted in developing the new adjustment procedures, these UCR county-level files are not official FBI UCR releases and are being provided for research purposes only. Users with questions regarding these UCR county-level data files can contact the National Archive of Criminal Justice Data at the ICPSR.

Two major changes to the UCR county-level files were implemented with the 1994 data and are continued through the 2010 data. A new imputation algorithm to adjust for incomplete reporting by individual law enforcement jurisdictions has been adopted. Also, a new Coverage Indicator has been created to provide users with a diagnostic measure of aggregated data quality in a particular county. These developments are described in greater detail below. The changes were instituted in response to comments from a number of users and after almost a year of discussions by UCR file users, the FBI, the Bureau of Justice Statistics, and the Inter-university Consortium for Political and Social Research. These changes result in a break in series from previous UCR county-level files. Data from earlier year files should not be compared to data from 1994 and subsequent years. Changes in procedures used to adjust for incomplete reporting at the ORI or jurisdiction level may be expected to have an impact on aggregates for counties in which some ORIs have not reported for all 12 months. However, the new adjustment procedures should result in county-level data that are less sensitive to changes between years in the extent of reporting by ORIs within a county. Consequently, data from 1994 forward should be more accurate estimates for longitudinal analysis.

CHANGES IN IMPUTATION PROCEDURES FOR INCOMPLETE REPORTING IMPUTATION PROCEDURES USED FOR 1977-1993 UCR COUNTY-LEVEL FILES:

The data for any ORI reporting 12 months were used for county aggregation as submitted. Data for an ORI reporting six to 11 months were increased by a weight of [12/months reported]. Data for any ORI reporting less than 6 months were deleted from the county total, and the population served by that ORI was deleted from the county population total to help control for differential data quality across counties.


The aim of this procedure was to produce comparable data cross-sectionally across all counties. However, if there were major changes in the ORIs that reported in a county across years, artifactual changes in the longitudinal data for a county could be introduced because of potential variation in the type of ORIs used to compute imputed county totals and rates each year.

IMPUTATION PROCEDURES USED FOR 1994 UCR COUNTY-LEVEL FILES AND ONWARD:

The data for any ORI reporting 12 months were used for county aggregation as submitted. Data for an ORI reporting 3 to 11 months were increased by a weight of [12/months reported]. For ORIs reporting 0 to 2 months in the arrest files or 1 to 2 months in the crimes reported files, data for these ORIs were set to zero and then data were estimated using rates calculated from ORIs reporting 12 months of data located in the ORI's geographic stratum based on UCR Population Groups within their state. UCR Population Groups are defined as follows:


Population Group
----------------

1) Cities 250,000 and over
2) Cities 100,000 - 249,999
3) Cities 50,000 - 99,999
4) Cities 25,000 - 49,999
5) Cities 10,000 - 24,999
6) Cities 2,500 - 9,999
7) Cities under 2,500
8) Non-MSA counties and non-MSA State Police
9) MSA counties and MSA State Police


There is an important distinction in estimation procedures for the arrest versus the crimes reported files. For the arrest files (Parts 1-3 and 5-7), data were estimated for agencies reporting 0-2 months based on the procedures mentioned above. However, due to the structure of the original data received from the FBI, ICPSR was only able to estimate data for agencies reporting 1-2 months in the crimes reported files (Parts 4 and 8). No estimations are provided for agencies reporting 0 months. To assist users, the county population figures and number of agencies reporting for both the arrest and crimes reported data files were added to the crimes reported files.


These variables provide users with information that can be used to determine the proportion of the population or agencies not included in the crime reported files due to the absence of records for agencies reporting 0 months. Users should keep in mind these differences when doing their analyses.

For releases of UCR county-level files before 1994, data from jurisdictions reporting less than 6 months of data were not included in county totals in an effort to ensure cross-sectional data comparability and quality. With the new procedures to adjust for incomplete reporting, data will be provided for each active ORI that reports less than 12 months of data, whether through weighting of partial year data or substitution of a value based on population group and state. Instead of exercising an a priori judgment that 6 months of data is the minimum threshold for acceptable data quality, a new Coverage Indicator variable has been created that will allow users to set their own threshold for acceptable data quality and to include or exclude data based on the standards they set themselves. The Coverage Indicator variable represents the proportion of county data that is reported for a given year. The indicator ranges from 0 to 100. A value of 0 indicates that no data for the county were reported and all data have been imputed. A value of 100 indicates that all ORIs in the county reported for all 12 months in the year. Coverage Indicator is calculated as follows:

CI_x = 100 * ( 1 - SUM_i { [ORIPOP_i/COUNTYPOP] * [ (12 - MONTHSREPORTED_i)/12 ] } )

where CI = Coverage Indicator
x = county
i = ORI within county

Some ORIs do not have a population associated with their jurisdiction. These ORIs report for jurisdictions such as national parks, colleges and universities, toll bridges and tunnels, and most state police departments. As the coverage indicator is based on months of reporting and the population of each agency, this variable will not show estimation that did occur for statewide ORIs and for ORIs as listed above that do not have a population but reported 3 to 11 months of data. Conversely, the coverage indicator will indicate that estimation has occurred for ORIs with a population that reported 3 to 11 months of data even if the ORIs actually reported no crimes or arrests. Similarly, the coverage indicator will indicate that estimation had occurred for ORIs with a population that reported 0 to 2 months of arrest data and 1 to 2 months of crimes reported data, even though no rate was calculated to estimate data because of the lack of ORIs in the agency's geographic stratum reporting 12 months of data. Finally, since data for ORIs that reported 0 to 2 months of arrest and 1 to 2 months of crime are set to zero, users should be aware that no estimation of data was possible for ORIs in these categories without a population. In the crimes reported files, no estimation was possible for agencies reporting 0 months because population figures for these agencies were not provided in the original files from the FBI.

"Crime in the United States 2010" is a publication prepared by the Federal Bureau of Investigation and provides estimations of national reported crime activity and arrest statistics from law enforcement agencies in the UCR Program. Users of this data collection prepared by ICPSR may not be able to match the statistics presented in "Crime in the United States 2010" due to several factors:

(1) The UCR staff continue to update agency records when additions or corrections are received by the UCR Program. The FBI statistics presented in "Crime in the United States 2010" are based on the data that the FBI has received prior to their established publication deadlines. The data used by ICPSR to prepare the data in ICPSR 33523 may contain additions or corrections to the data submitted to the FBI after their publication deadline for producing "Crime in the United States 2010."

(2) The new imputation algorithm that ICPSR implemented in 1994 approximates the estimation procedures that the FBI uses to adjust for incomplete or unreported data from individual law enforcement jurisdictions. Limited or no crime or arrest data were available for some states in 2010. For some tables in "Crime in the United States 2010" (for example, Section II, Table 2: Total Crime Counts in the United States, and Section IV, Table 29: Estimated Arrests), the FBI provided estimated crime counts and arrest totals for some of these states (see Appendix I -- Methodology for the FBI's estimation methods). The ICPSR algorithm estimates data for agencies reporting less than three months of data by calculating rates from agencies reporting 12 months of data located in the agency's geographic stratum within that state. Since data for these states were very limited or not present in the original data, estimates for the entire state could not be produced by ICPSR.

(3) Some tables in "Crime in the United States 2010" were prepared using data only from agencies submitting complete reports for the 12 months for 2010 prior to the publication deadline (for example, Section IV, Table 69: Arrests by State). For this ICPSR data collection, all law enforcement agency records present in the original FBI data were used in the aggregation to the county level. County records with a coverage indicator value of 100 contain only 12-month reporting agencies (see last paragraph of the Coverage Indicator section in the Introduction for possible exceptions). Agencies reporting 12 months of data within a county with a coverage indicator value less than 100 cannot be separately identified in this dataset aggregated at the county level.

In this data collection, zeroes may represent both true zeroes or missing data, and it is possible to distinguish between the two. In the arrest files (Parts 1-3 and 5-7), the coverage indictor alone does not indicate whether or not zeroes are true or missing values. A county can have a coverage indicator of zero, but still contain arrest data. ICPSR can estimate arrest data for a county that did not report any arrests based on data for other counties of comparable population size in the same state that did report 12 months of data. In order to distinguish true zeroes from missing values, the user has to look at the coverage indicator for a county in conjunction with the arrest variables. If an arrest variable for a particular county has a value of zero and the coverage indicator is greater than zero, then the arrest variable contains a true zero. This true zero is not necessarily a reported zero as it may have been estimated. If an arrest variable for a particular county has a value of zero and the coverage indicator for that county is zero, then the user must check the values of ALL of the arrest variables. If some arrest variables contain zeroes and some contain other values, then the zeroes for this county are true. If ALL arrest variables and the coverage indicator for the county in question contain zeroes, then these indicate missing data.

In the crimes reported file (Part 4), data can not be estimated for non-reporting agencies. Therefore, counties with no population for reporting agencies will also have a coverage indicator of zero and all crime variables will have a value of zero. These zeroes indicate missing data. If a county has one or more offense variables with a value of zero, but has a value of greater than zero for the population and coverage indicator variables, then the zeroes for these particular offense variables should be considered true zeroes for the purposes of analysis.