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FBI Arrest Statistics: 1994-2011


Methods

Data collection [back to top]

The Uniform Crime Reporting (UCR) Program within the Federal Bureau of Investigation (FBI) originally collected the data used in this work. Each year the FBI's UCR Program collects monthly counts of arrests from thousands of law enforcement agencies. Some law enforcement agencies report a complete 12 months of data. Others report less. Some law enforcement agencies do not report at all. These data are the basis for the FBI's annual Crime in the United States reports. A detailed discussion of the FBI's reporting procedures can be found in the Uniform Crime Reporting Handbook (U.S. Government Printing Office, 1980).

Most law enforcement agencies have jurisdiction over a geographical area that is within the boundaries of a single county. Some, however, have jurisdiction over an area that spans county boundaries. For example, a large metropolitan department may have responsibility for all of one county and a part of a contiguous county. When an arrest is made, the arrest is assigned to the county in which the department is headquartered, even though the arrest may have occured in the other county. In such instances, the population served by the departments in the county is greater than the population living within the geographic boundaries of the county. The population displayed on the Easy Access arrest tables is the population served by the law enforcement agencies that are based in that county. Therefore, the displayed population for a county may be greater, or less, than the actual population living in that county.

Estimation procedure [back to top]

The FBI provides their annual data files containing agency-based arrest counts to the National Archive of Criminal Justice Data (NACJD) within the Inter-university Consortium for Political and Social Research (ICPSR) at the University of Michigan. With funds from the Bureau of Justice Statistics, NACJD aggregates agency-level counts to the county level, and then applies an estimation procedure to compensate for the underreporting and nonreporting agencies within the county.

The citations for the county level data files prepared by ICPSR are as follows:

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U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2011 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2013. [ View 2011 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2010 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2012. [ View 2010 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2009 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2012. [ View 2009 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2008 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2011. [ View 2008 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2007 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2009. [ View 2007 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2006 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2008. [ View 2006 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2005 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2007. [ View 2005 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2004 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2006. [ View 2004 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2003 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2005. [ View 2003 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2002 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2004. [ View 2002 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2001 [Computer file]. 1st ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2003. [ View 2001 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 2000 [Computer file]. 3rd ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2002. [ View 2000 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 1999 [Computer file]. 3rd ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2002. [ View 1999 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 1998 [Computer file]. 2nd ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2001. [ View 1998 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 1997 [Computer file]. 2nd ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2001. [ View 1997 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 1996 [Computer file]. 3rd ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2001. [ View 1996 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 1995 [Computer file]. 2nd ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2001. [ View 1995 Codebook (PDF file) ]

U.S. Dept. of Justice, Federal Bureau of Investigation. UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: COUNTY-LEVEL DETAILED ARREST AND OFFENSE DATA, 1994 [Computer file]. 3rd ICPSR ed. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 2001. [ View 1994 Codebook (PDF file) ]

A detailed description of the county-level files prepared by NACJD that present county-level arrest estimates is presented below. The material that follows borrows heavily from the codebook prepared by ICPSR staff to document their 2000 data file release (ICPSR 3451).

With consultation from the FBI's Uniform Crime Reporting Program staff, NACJD developed a procedure to impute arrest counts. It should be noted that the county-level estimates are not official FBI releases and are being provided for research purposes only. The imputation algorithm to adjust for incomplete reporting by individual law enforcement jurisdictions is as follows. The data for any law enforcement agency (or ORI) reporting for all 12 months in a calendar year is used for county aggregation as submitted. Data for an ORI reporting 3 to 11 months is increased by a weight of twelve divided by the number of months reported. For ORIs reporting 0 to 2 months, the counts are estimated using rates calculated from ORIs reporting 12 months of data located within the same state and having the same population group. The UCR population groups are defined as follows:

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

Data from agencies reporting only statewide figures are allocated to the counties in the state in proportion to each county's share of the state population, except in Alaska and Vermont, where State Police records are reported.

National estimates for the total number of arrests in the U.S. displayed by Easy Access are not based on the information contained in the NACJD data file, but instead are based on information presented in the FBI's annual Crime in the United States reports. Each Crime in the United States report presents the FBI's national estimates of arrests within the individual offense categories. In the Crime in the United States publications, the FBI also reports the percentage of all arrests in an offense category that were arrests of juveniles (i.e., persons under age 18). NCJJ applied these proportions to the national arrest estimates to develop national estimates of the number of juvenile and adult arrests within each offense category.

Coverage Indicator [back to top]

The data presented in Easy Access to FBI Arrest Statistics are based on estimates that account for missing data. The Coverage Indicator represents the proportion of the county (or state) population for which arrest counts were available for a given year and for which no estimates were required. The indicator ranges from 100%, indicating that all ORIs in the county (or state) reported for 12 months in the year, to 0%, indicating that all data in the county (or state) are based on estimates rather than reported data. For example, a coverage indicator of 90% means that 90% of the population of the county (or state) provided arrest data. Arrest estimates were developed for the remaining 10% of the population. A county's coverage indicator is the sum of the following statistic for each ORI in the county:

100 * (ORI population / county population) * (months reported / 12)

A state's coverage indicator is calculated similarly. The coverage indicators for the United States are taken from the annual Crime in the United States reports.

In many jurisdictions, data reported to the FBI are incomplete. The lower the coverage indicator, the greater the likelihood that the estimates do not accurately reflect the arrest activities of the jurisdiction. As a result, only jurisdictions with a coverage indicator at or above 90% are displayed in Easy Access to FBI Arrest Statistics. Click on the Data Coverage tab to find out what years of data are available for your jurisdiction of interest.

Comparing with Crime in the United States [back to top]

Crime in the United States is a publication series prepared by the Federal Bureau of Investigation and provides national estimates of reported crimes and arrests based on data provided by law enforcement agencies to the UCR Program. Users of the data prepared by NACJD and presented by Easy Access may not be able to match the county and state arrest statistics presented in the corresponding annual Crime in the United States report due primarily to two factors.

First, the UCR staff continues to update agency records when the UCR Program receives additions or corrections. The FBI statistics presented in Crime in the United States are based on the data that the FBI received prior to their established publication deadlines. The data used by NACJD to prepare their annual county-level estimates may contain data submitted to the FBI after their publication deadline for producing the Crime in the United States report, or corrections to the published data.

Second, some tables in Crime in the United States are prepared using data only from agencies submitting complete reports for the 12 months in the calendar year. However, for the estimates presented in Easy Access, all law enforcement agency records present in the original FBI data are used in the aggregation to the county level. County records with a coverage indicator value of 100% indicate that there was complete 12-month reporting by all agencies in the county.

Population data [back to top]

The FBI provides NACJD with annual estimates of the total population served by each law enforcement agency along with each agency's reported counts of arrests. The populations of the agencies in each county are summed by NACJD to generate an estimate of each county's annual total population. Estimates of each county's adult (i.e., persons ages 18 and over) and juvenile (i.e., persons ages 10 through 17) populations are developed by the National Center for Juvenile Justice using the FBI's estimate of total county populations and data files prepared by the National Center for Health Statistics (NCHS) and the U.S. Bureau of the Census (Census). The NCHS and Census files provide annual estimates of the number of persons of each age group living in each county in the U.S. The citation for these files:

1994-1999 population data:

National Center for Health Statistics (2004). Bridged-race intercensal estimates of the July 1, 1990-July 1, 1999, United States resident population by county, single-year of age, sex, race, and Hispanic origin. [Released on 7/26/2004; Retrieved 9/15/2004]. Prepared by the U.S. Census Bureau with support from the National Cancer Institute. Available on-line at: http://www.cdc.gov/nchs/nvss/bridged_race.htm.

2000-2009 population data:

National Center for Health Statistics (2012). Intercensal estimates of the resident population of the United States for July 1, 2000-July 1, 2009, by year, county, single-year of age (0, 1, 2, .., 85 years and over), bridged race, Hispanic origin, and sex. [Released 10/26/2012; Retrieved 10/26/2012]. Prepared under a collaborative arrangement with the U.S. Census Bureau. Available online from http://www.cdc.gov/nchs/nvss/bridged_race.htm as of October 26, 2012, following release by the U.S. Census Bureau of the unbridged intercensal estimates by 5-year age group on October 9, 2012.

2010-Present population data:

National Center for Health Statistics (2012). Postcensal estimates of the resident population of the United States for July 1, 2010-July 1, 2011, by year, county, single-year of age (0, 1, 2, .., 85 years and over), bridged race, Hispanic origin, and sex (Vintage 2011). [Released 5/18/2012; Retrieved 7/19/2012]. Prepared under a collaborative arrangement with the U.S. Census Bureau. Available online from http://www.cdc.gov/nchs/nvss/bridged_race.htm as of July 18, 2012, following release by the U.S. Census Bureau of the unbridged Vintage 2011 postcensal estimates by 5-year age group on May 17, 2012.

To develop annual estimates of a county's adult population consistent with the FBI's annual total population for the county, the percentage of each county's total population age 18 or older is calculated for each year using information from the NCHS and Census data files. Each year's adult percentage is then multiplied by the FBI's estimate of the county's total population to yield an estimate of the county's adult population consistent with the FBI's population estimates. Correspondingly, to calculate a county's juvenile population, the juvenile percentage is calculated and multiplied by the FBI's estimate of the county's total population. The resulting populations are used to calculate the adult and juvenile arrest rates. Total rates are based on the FBI's estimate of each county's total population.

Additional notes [back to top]

In the UCR county-level files, the population and arrest data for agencies spanning multiple counties are assigned to the county containing the largest population component of the agencies. Counties containing smaller population components of multiple-county agencies will contain no population or arrest data for these agencies.

Cities designated by the Census Bureau as independent cities are reported separately. Some agencies, such as state parks and some State Police, provide data only on a statewide basis. In most of these cases, data are allocated to counties proportionate to their share of the total state population. Finally, the original data from the FBI contain one record for the New York City Police Department (NYPD). Data from the NYPD are allocated by NACJD into the five counties it serves based on the proportion of the NYPD population in each county. For example, the population served by the NYPD in Queens County is divided by the total population served by the NYPD in all five counties and the resulting proportion is multiplied by the arrest data from the NYPD to apportion arrest data to Queens County.

Prior to 1997, arrests made by the New York / New Jersey Port Authority were allocated to the specific counties in which an arrest was made. Beginning in 1997, the New Jersey arrests were assigned to a single Port Authority record and the New York arrests were placed in New York County.

Table notes [back to top]

Easy Access to FBI Arrest Statistics displays data for jurisdictions with coverage indicators at or above 90% in a given year. When the coverage indicator for a jurisdiction is below 90%, no data are displayed for that year. Click on the Data Coverage tab to find out what years of data are available for your jurisdiction of interest.