Uniform Crime Reporting Program Data: County-Level Detailed Arrest and Offense Data, United States, 2013 (ICPSR 36117)

1. Two major changes to the Uniform Crime Reports (UCR) county-level files were implemented beginning with the 1994 data. A new imputation algorithm to adjust for incomplete reporting by individual law enforcement jurisdictions was adopted. Within each county, data from agencies reporting 3 to 11 months of information were weighted to yield 12-month equivalents. Data for agencies reporting less than three months of data were replaced with data estimated by rates calculated from agencies reporting 12 months of data located in the agency's geographic stratum within its state. Secondly, a new Coverage Indicator was created to provide users with a diagnostic measure of aggregated data quality in a particular county. Data from agencies reporting only statewide figures were allocated to the counties in the state in proportion to each county's share of the state population.

2. In the arrest files (Parts 1-3 and 5-7), data were estimated for agencies reporting zero months based on the procedures mentioned above. However, due to the structure of the data received from the Federal Bureau of Investigation (FBI), estimations could not be produced for agencies reporting zero months in the crimes reported files (Parts 4 and 8). Offense data for agencies reporting one or two months are estimated using the above procedures. Users are encouraged to refer to the codebook for more information.

3. No arrest data were provided for Alabama, Florida, and Illinois. Limited arrest data were provided for South Dakota. Limited crimes reported data were available for Alaska, Illinois, Mississippi, and South Dakota.

4. UCR program staff at the Federal Bureau of Investigation (FBI) were consulted in developing the new adjustment procedures. However, 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 ICPSR.

• United States Department of Justice. Federal Bureau of Investigation. Uniform Crime Reporting Program Data: County-Level Detailed Arrest and Offense Data, United States, 2013. ICPSR36117-v2. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2017-09-12. http://doi.org/10.3886/ICPSR36117.v2

2017-09-12 Arrest data for the counties of Bronx, Kings, New York, Queens, and Richmond in the state of New York are blanked by ICPSR due to discrepancies in the original data.

2016-12-14 Arrest data for Carroll County in Indiana and Monroe County in Mississippi are updated.