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
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.
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.
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.