Home About Us CJIS UCR Crime in the U.S. 2011 Crime in the U.S. 2011 Methodology

Methodology

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Law enforcement agencies that participate in the Uniform Crime Reporting (UCR) Program forward crime data through their state UCR Programs in 46 states and the District of Columbia.  Local agencies in those states that do not have a state program submit crime statistics directly to the FBI, which provides continuous guidance and support to those participating agencies.  The state UCR Programs function as liaisons between local agencies and the FBI.  Many states have mandatory reporting requirements, and many state UCR Programs collect data beyond those typically called for by the national UCR Program to address crime problems specific to their particular jurisdictions.  These state UCR Programs, in most cases, also provide direct and frequent service to their participating law enforcement agencies, make information readily available for statewide use, and help to streamline the national Program’s (FBI’s) operations.

Criteria for state UCR Programs

The criteria established for state Programs ensure consistency and comparability in the data submitted to the national Program, as well as regular and timely reporting.  These criteria are:

(1) The state Program must conform to the national UCR Program standards, definitions, and information required. 

(2) The state criminal justice agency must have a proven, effective, statewide program and have instituted acceptable quality control procedures. 

(3) The state crime reporting must cover a percentage of the population at least equal to that covered by the national UCR Program through direct reporting.

(4) The state program must have adequate field staff assigned to conduct audits and to assist contributing agencies in record-keeping practices and crime-reporting procedures.

(5) The state Program must furnish the FBI with all of the detailed data regularly collected by the FBI from individual agencies that report to the state Program in the form of duplicate returns, computer printouts, and/or appropriate electronic media.

(6) The state Program must have the proven capability (tested over a period of time) to supply all the statistical data required in time to meet the publication deadlines of the national UCR Program.

Data completeness and quality

In order to fulfill its responsibilities in connection with the UCR Program, the FBI edits and reviews individual agency reports for both completeness and quality.  Members of the national Program’s staff contact the state UCR Program in connection with crime-reporting matters and, as necessary, when approved by the state, individual contributors.  Upon request, staff members conduct training programs within the state on law enforcement record-keeping and crime-reporting procedures.  Following audit standards established by the federal government, the FBI conducts an audit of each state’s UCR data collection procedures once every 3 years.  Should circumstances develop whereby the state Program does not comply with the aforementioned requirements, the national Program may institute a direct collection of data from law enforcement agencies within the state.

Reporting procedures 

Offenses known and value of property—Law enforcement agencies tabulate the number of Part I offenses brought to their attention based on records of all reports of crime received from victims, officers who discover infractions, or other sources, and submit them each month to the FBI either directly or through their state UCR Programs.  Part I offenses include murder and nonnegligent manslaughter, forcible rape, robbery, aggravated assault, burglary, larceny-theft, motor vehicle theft, and arson.  Law enforcement agencies also submit monthly to the FBI the value of property stolen and recovered in connection with the offenses and detailed information pertaining to criminal homicide.

Unfounded offenses and clearances—When, through investigation, an agency determines that complaints of crimes are unfounded or false, the agency eliminates that offense from its crime tally through an entry on the monthly report.  The report also provides the total number of actual Part I offenses, the number of offenses cleared, and the number of clearances that involve only offenders under the age of 18.  (Law enforcement can clear crimes in one of two ways:  by the arrest of at least one person who is charged and turned over to the court for prosecution or by exceptional means—when some element beyond law enforcement’s control precludes the arrest of a known offender.) 

Persons arrested—In addition to reporting Part I offenses, law enforcement agencies provide monthly to the UCR Program data on the age, sex, and race of persons arrested for Part I and Part II offenses.  Part II offenses encompass all crimes, except traffic violations, that are not classified as Part I offenses.

Officers killed or assaulted—Law enforcement agencies also report monthly to the UCR Program information regarding law enforcement officers killed or assaulted, and yearly, the number of full-time sworn and civilian law enforcement personnel employed as of October 31.

Hate crimes—At the end of each quarter, law enforcement agencies report summarized data on hate crimes, i.e., specific offenses that were motivated by an offender’s bias against the perceived race, religion, ethnic/national origin, sexual orientation, or physical or mental disability of the victim.  Those agencies participating in the UCR Program’s National Incident-Based Reporting System (NIBRS) submit hate crime data monthly.

Editing procedures           

The UCR Program thoroughly examines each report it receives for arithmetical accuracy and for deviations in crime data from month to month and from present to past years’ data that may indicate errors.  The UCR staff members compare aggregated data from agencies of similar population size to identify any unusual fluctuations in an agency’s crime counts.  Large variations in crime levels may indicate modified records procedures, incomplete reporting, or changes in the jurisdiction’s geopolitical structure.

Evaluation of trends—Data reliability is a high priority of the FBI, which brings any deviations or arithmetical adjustments to the attention of state UCR Programs or the submitting agencies.  Typically, FBI staff members study the monthly reports to evaluate periodic trends prepared for individual reporting units.  Any significant increase or decrease becomes the subject of a special inquiry.  Changes in crime reporting procedures or annexations that affect an agency’s jurisdiction can influence the level of reported crime.  When this occurs, the FBI excludes the figures for specific crime categories or totals, if necessary, from the trend tabulations.

Training for contributors—In addition to the evaluation of trends, the FBI provides training seminars and instructional materials on crime reporting procedures to assist contributors in complying with UCR standards.  Throughout the country, the national Program maintains liaison with state UCR Programs and law enforcement personnel and holds training sessions to explain the purpose of the program, the rules of uniform classification and scoring, and the methods of assembling the information for reporting.  When an individual agency has specific problems in compiling its crime statistics and its remedial efforts are unsuccessful, personnel from the FBI’s Criminal Justice Information Services Division may visit the contributor to aid in resolving the difficulties.

UCR Handbook—The national UCR Program publishes the Uniform Crime Reporting Handbook (revised 2004), which details procedures for classifying and scoring offenses and serves as the contributing agencies’ basic resource for preparing reports.  The national staff also produces letters to UCR contributors, State Program Bulletins, and UCR Newsletters as needed.  These provide policy updates and new information, as well as clarification of reporting issues.

The final responsibility for data submissions rests with the individual contributing law enforcement agency.  Although the FBI makes every effort through its editing procedures, training practices, and correspondence to ensure the validity of the data it receives, the accuracy of the statistics depends primarily on the adherence of each contributor to the established standards of reporting.  Deviations from these established standards that cannot be resolved by the national UCR Program may be brought to the attention of the Criminal Justice Information Systems Committees of the International Association of Chiefs of Police and the National Sheriffs’ Association.

Population estimation  

The FBI calculated 2011 state growth rates using the U.S. Census Bureau’s 2010 decennial state/national population figures and 2011 provisional state/national population estimates.  The FBI then estimated population figures for city jurisdictions by applying the 2011 state growth rate to the 2010 U.S. Census Bureau data.

Population estimates for 2011 are based on the percent change in the state population from the U.S. Census Bureau’s 2009 revised estimates and 2010 decennial totals.  Population estimates for 2007 are based on the percent change in the state population from the U.S. Census Bureau’s 2006 revised estimates and 2007 provisional estimates.  Population estimates for 2002 are based on the percent change in the state population from the U.S. Census Bureau’s 2001 revised estimates and 2002 provisional estimates.

NIBRS conversion

Thirty-two state UCR Programs are certified to provide their UCR data in the expanded NIBRS format; based on 2011 data submissions, 15 states submit all their data via the NIBRS.  For presentation in this book, the NIBRS data were converted to the historical Summary Reporting System data.  The UCR Program staff constructed the NIBRS database to allow for such conversion so that the UCR Program’s long-running time series could continue.

Crime trends

By showing fluctuations from year to year, trend statistics offer the data user an added perspective from which to study crime.  Percent change tabulations in this publication are computed only for reporting agencies that provided comparable data for the periods under consideration.  The FBI excludes from the trend calculations all figures except those received for common months from common agencies.  Also excluded are unusual fluctuations of data that the FBI determines are the result of such variables as improved records procedures, annexations, etc.

Caution to users

Data users should exercise care in making any direct comparison between data in this publication and those in prior issues of Crime in the United States.  Because of differing levels of participation from year to year and reporting problems that require the FBI to estimate crime counts for certain contributors, some data may not be comparable from year to year.  In addition, this publication may contain updates to data provided in prior years’ publications.  For example, because of the receipt of additional data after the 2010 publication deadline, the 2010 Supplementary Homicide Report (SHR) data in last year’s publication may not match the 2010 SHR data in this 2011 publication.

2011 arrest data considerations

  • Limited arrest data were received from Illinois.  Arrest counts were received for Chicago and Rockford only.
  • Except for the cities of Minneapolis and St. Paul, the Minnesota state UCR Program’s guidelines for reporting forcible rape arrest counts do not comply with the national UCR Program’s guidelines; i.e., Minnesota data include arrests made for forcible rapes of male victims.  Therefore, the state forcible rape counts that are published include only the totals received from Minneapolis and St. Paul.
  • For 2011, only arrest totals (with no age or gender breakdowns) are available for Florida.  Therefore, Florida arrest totals are included only in Table 69, “Arrests by State, 2011.”
  • No 2011 arrest data were received from the District of Columbia’s Metropolitan Police Department.  The two agencies in the District of Columbia for which 12 months of arrest data were received, the Metro Transit Police and the National Zoological Park, have no attributable population.
  • No 2011 arrest data were received from the New York City Police Department.  However, arrest totals for this agency were estimated by the national UCR Program and were included in Table 29 “Estimated Number of Arrests, United States, 2011.”
  • Beginning with Crime in the United States, 2010, the national UCR Program discontinued publishing data for runaways.

Offense estimation

Tables 1 through 5 and Table 7 of this publication contain statistics for the entire United States.  Because not all law enforcement agencies provide data for complete reporting periods, the FBI includes estimated crime numbers in these national presentations.  The FBI estimates data for three areas:  Metropolitan Statistical Areas (MSAs), cities outside MSAs, and nonmetropolitan counties.  The FBI computes estimates for participating agencies not providing 12 months of complete offense data.  For agencies supplying 3 to 11 months of offense data, the national UCR Program estimates for the missing data by following a standard estimation procedure using the data provided by the agency.  If an agency has supplied less than 3 months of data, the FBI computes estimates by using the known crime figures of similar areas within a state and assigning the same proportion of crime volumes to nonreporting agencies.  The estimation process considers the following:  population size covered by the agency; type of jurisdiction, e.g., police department versus sheriff’s office; and geographic location. 

Estimation of state-level data

In response to various circumstances, the FBI calculates estimated offense totals for certain states.  For example, some states do not provide forcible rape figures in accordance with UCR guidelines.  In addition, problems at the state level have, at times, resulted in no useable data.  Also, the efforts to convert to the NIBRS have contributed to the need for unique estimation procedures.  A summary of state-specific and offense-specific estimation procedures follows.

State

Year(s)

Reason for Estimation

Estimation Method

Delaware

1998

The state UCR Program was unable to provide forcible rape figures in accordance with national UCR guidelines.

The forcible rape total was estimated by reducing the number of reported offenses by the proportion of male forcible rape victims statewide.

Florida

1996

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

The state UCR Program was able to provide an aggregated state total; data received from 94 individual Florida agencies are shown in the 1996 jurisdictional figures presented in Tables 8 through 11.

Hawaii

2011

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

Since 12 months of data were not received from any individual Hawaii agencies, the FBI estimated for the missing data following standard estimation procedures and manual estimation procedures to arrive at a 2011 state total.

Illinois

 

 

 

 

1991 1992 1993 1994

The state UCR Program was unable to provide forcible rape figures in accordance with UCR guidelines.

The rape totals were estimated using national rates per 100,000 inhabitants within the eight population groups and assigning the forcible rape volumes proportionally to the state.

1993 1994

NIBRS conversion efforts resulted in estimation.

1993–Since valid annual totals were available for approximately 60 Illinois agencies, those counts were maintained.  The counts for the remaining jurisdictions were replaced with the most recent valid annual totals or were generated using standard estimation procedures.  The results of all sources were then combined to arrive at the state total.

1994–State totals were generated using only the valid crime rates for the East North Central Division.  Within each population group, the state’s offense totals were estimated based on the rate per 100,000 inhabitants within the remainder of the geographic division.

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

 

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

Valid violent crime and property crime offense counts, with the exception of forcible rape, were available for most of the largest cities (100,000 and over in population).  For other agencies, the only available counts generated by the Illinois state UCR Program were state totals based upon an incident-level system without indication of multiple offenses recorded within single incidents.  Therefore, the UCR Hierarchy Rule could not be applied in order to convert the state’s data to Summary Reporting System data.  (The Hierarchy Rule requires that only the most serious offense in a multiple-offense criminal incident is counted.)  To arrive at a comparable state estimate to be included in national compilations, the Illinois state UCR Program’s state totals (which were inflated because of the nonapplication of the Hierarchy Rule) were reduced by the proportion of multiple offenses reported within single incidents in the NIBRS database.  Valid totals for the large cities were excluded from the reduction process.

2006 2007 2008 2009

 

The state UCR Program was unable to provide forcible rape figures in accordance with UCR guidelines.

Forcible rape figures for Rockford include only the forcible rape offenses with female victims that were extracted from the agency’s NIBRS data.

To derive the state forcible rape estimate, the percentage of female forcible rape victims was extracted from all NIBRS incidents in which a forcible sex offense was reported.  That percentage was applied to the forcible rape count received from the Illinois state UCR Program.

Iowa

1991

NIBRS conversion efforts resulted in estimation.

State totals were estimated by updating previous valid annual totals for individual jurisdictions, subdivided by population group.  Percent changes for each offense within each population group of the West North Central Division were applied to the previous valid annual totals.  The state totals were compiled from the sums of the population group estimates.

Kansas

1993 1994

NIBRS conversion efforts resulted in estimation.

1993–State totals were estimated by updating previous valid annual totals for individual jurisdictions, subdivided by population group.  Percent changes for each offense within each population group of the West North Central Division were applied to the previous valid annual totals.  The state totals were compiled from the sums of the population group estimates.

1994–State totals were generated using only the valid crimes rates for the West North Central Division.  Within each population group, the state’s offense totals were estimated based on the rate per 100,000 inhabitants within the remainder of the geographic division.

1995 1996 1997 1998 1999 2000

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

1995–The state UCR Program was able to provide valid 1994 state totals which were then updated using 1995 crime trends for the West North Central Division.

1996–The Kansas state estimate was extrapolated from 1996 January-June state totals provided by the Kansas state UCR Program.

1997–The Kansas state estimate was extrapolated from 1996 January-June state totals provided by the Kansas state UCR Program.

1998–To arrive at 1998 estimates, 1997 state totals supplied by the Kansas state UCR Program were updated using 1998 crime trends for the West North Central Division.

1999–To arrive at 1999 estimates, 1998 state totals supplied by the Kansas state UCR Program were updated using 1999 crime trends for the West North Central Division.

2000–To arrive at 2000 estimates, 1999 state estimates were updated using 2000 crime trends for the West North Central Division.


 

Kentucky

1996 1997 1998 1999 2000 2001 2002 2003

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

1996–The 1995 and 1996 percent changes within the East South Central Division were applied to valid 1995 state totals to generate 1996 state totals.

1997–The 1996 and 1997 percent changes registered for the East South Central Division were applied to valid 1996 state totals to effect 1997 state totals.

1998–State totals were estimated by using 1997 figures for the nonreporting areas and applying 1997 versus 1998 percent changes in the East South Central Division.  The estimates for the nonreporting areas were then increased by any actual 1998 crime counts received.

1999–To arrive at 1999 estimates, 1998 state totals supplied by the Kentucky state UCR Program were updated using 1999 crime trends for the East South Central Division.

2000–To arrive at 2000 estimates, 1999 state totals supplied by the Kentucky state UCR Program were updated using 2000 crime trends for the East South Central Division.

 

2001–To arrive at the 2001 estimates, the 2000 state estimates were updated using 2001 crime trends reported for the East South Central Division.

2002–To obtain the 2002 state crime counts, the FBI contacted the state UCR Program, and the state agency provided their latest state totals, 2000.  Therefore, the 2001 state estimates were updated for inclusion in the 2002 edition of Crime in the United States by using the 2001 crime trends for the East South Central Division.  To derive the 2002 state estimate, the 2002 crime trends for the geographic division were applied to the adjusted 2001 state estimate. 

2003–To obtain the 2003 estimates, the 2003 crime trends for the East South Central Division were applied to adjusted 2002 state estimates.  The 2002 state counts were reestimated by applying the 2002 crime trends for the East South Central Division using more current figures, 2001 totals provided by the state UCR Program.  The adjusted 2002 estimates differ from the figures published in the 2002 edition of Crime in the United States which were originally estimated using 2001 totals.

 

Maine

1999

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

The Maine Department of Public Safety forwarded monthly January through October crime counts for each law enforcement contributor; since 12 months of data were not received, the FBI estimated for the missing data following standard estimation procedures to arrive at a 1999 state total.

Michigan

1993

The state UCR Program was unable to provide forcible rape figures in accordance with UCR guidelines.

The rape total was estimated using national rates per 100,000 inhabitants within the eight population groups and assigning the forcible rape volumes proportionally to the state.

Minnesota

1993 2005 2006 2007 2008 2009

2010

2011

The state UCR Program was unable to provide forcible rape figures in accordance with UCR guidelines.

1993–The rape total was estimated using national rates per 100,000 inhabitants within the eight population groups and assigning the forcible rape volumes proportionally to the state.

2005–To arrive at a comparable state estimate for forcible rape offenses to be included in national compilations, Minnesota’s forcible rape total was estimated by using the national rates per 100,000 inhabitants within the eight population groups and proportionally assigning forcible rape volumes to Minnesota’s population groups.

2006-2011–Valid forcible rape figures were available for Minneapolis and St. Paul.  To arrive at a comparable state estimate for forcible rape offenses to be included in national compilations, the rest of Minnesota’s forcible rape totals were estimated by using the national rates per 100,000 inhabitants within the eight population groups and proportionally assigning forcible rape volumes to Minnesota’s population groups.

Montana

1994 1995 1996 1997 1998 1999 2000

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

1994–State totals were estimated by updating previous valid annual totals for individual jurisdictions, subdivided by population group.  Percent changes for each offense within each population group of the Mountain Division were applied to the previous valid annual totals.  The state totals were compiled from the sums of the population group estimates.

1995–State estimates were computed by updating the previous valid annual totals using the 1994 versus 1995 percent changes for the  Mountain Division.

1996–The 1995 and 1996 percent changes within the Mountain Division were applied to valid 1995 state totals to generate 1996 state totals.

1997–The 1996 and 1997 percent changes registered for the Mountain Division, in which Montana is categorized, were applied to valid 1996 state totals to effect 1997 state totals.

1998–State totals were estimated by using 1997 figures for the nonreporting areas and applying 1997 versus 1998 percent changes for the Mountain Division.  The estimates for the nonreporting areas were then increased by any actual 1998 crime counts received.

1999–To arrive at 1999 estimates, 1998 state totals supplied by the Montana state UCR Program were updated using 1999 crime trends for the Mountain Division.

2000–To arrive at 2000 estimates, 1999 state totals supplied by the Montana state UCR Program were updated using 2000 crime trends for the Mountain Division.

New Hampshire

1997 1998 1999

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

1997–The 1996 and 1997 percent changes registered for the New England Division were applied to valid 1996 state totals to effect 1997 state totals.

1998–State totals were estimated by using 1997 figures for the nonreporting areas and applying 1997 versus 1998 percent changes for the New England Division.  The estimates for the nonreporting areas were then increased by any actual 1998 crime counts received.

1999–The state totals were estimated by using the 1998 figures for the 1999 nonreporting areas and applying the 2-year percent change for the New England Division.

Vermont

1997

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

The 1996 and 1997 percent changes registered for the New England Division were applied to valid 1996 state totals to effect 1997 state totals.

Wisconsin

1998

The state UCR Program was unable to provide complete offense figures in accordance with UCR guidelines.

State totals were estimated by using 1997 figures for the nonreporting areas and applying 1997 versus 1998 percent changes for the East North Central Division.  The estimates for the nonreporting areas were then increased by any actual 1998 crime counts received.

 

Table methodology

The tables in this report are based upon varying levels of data submissions.  For example, some participating agencies may submit data for some but not all months of the reporting year.  Using well-established procedures, the FBI estimates for missing offense data for agencies with partial reports and for nonreporting agencies and then aggregates these estimates with data reported to determine the number of offenses for each state and the Nation.  Tables 1–5, 7, and 29 present these approximations.  In addition, various circumstances require the FBI to estimate offense totals from time to time for some states.  (An explanation of the estimation procedures applied to particular states during specific reporting years is provided in the Offense Estimation section.)

To be included in Tables 8–11 and 21 and 22, which provide statistics for specific jurisdictions and states, agencies must submit 12 months of complete data prior to the FBI’s established deadlines.  To be included in Table 20, agencies must submit supplementary homicide data.  Tables 12–19, 23–28, 30–75, and 77 provide the number of reporting agencies (data source) and the total population covered by their collective jurisdictions.  To be included in Tables 78–81, agencies must submit officer and civilian law enforcement employee counts as of October 31.  For information on the classification of jurisdictions, see Area Definitions.

To view and/or print the methodology of a particular table, select the Data Declaration link on that specific table.  To download Portable Document Format, or PDF, files of the data declarations for every table in this publication, visit the Download Printable Files page and select Data Declarations and Overviews.