Government agencies, criminologists, and law enforcement personnel rely on official records and surveys to measure the extent of criminal behavior in the United States. Two of the most important primary sources of information and data are the Uniform Crime Report (UCR) and the National Crime Victimization Survey (NCVS).

The UCR began in 1930 as a method of measuring the overall crime rate in America. The UCR is a system of organization through which information and crime statistics from local law enforcement agencies nationwide are forwarded to the FBI. The FBI relies on the voluntary cooperation of law enforcement agencies and local police departments. The UCR divides the information on the criminal offenses it collects into two categories: Part I Offenses, which include more serious and violent crimes, and Part II Offenses, which include less serious crimes. The Part II Offenses include most of the crimes recorded in the UCR.

Unfortunately, reporting data to the FBI by local police authorities is voluntary. This creates at least three problems. First, many times the local agencies do not voluntarily report the data. Second, when multiple offenses are committed, many departments report only the most serious ones. Third, many people do not report instances where they are victimized by criminals.

The NCVS began in 1973 and was created to deal with the non-reporting problem. It is a national survey run by the US Census Bureau every year on behalf of the Bureau of Justice Statistics (BJS). The NCVS collects information from crime victims by means of interviews, which frequently uncover crimes never reported to the police.

Unfortunately, almost forty percent of property crimes and fifty percent of violent crimes remain unreported, despite the process employed by NCVS interviewers. Also, victims often misinterpret events and report them as crimes. For example, a window left ajar might be reported to an interviewer as an attempted burglary, though no police report was ever filed. Still, other victims of crime remain too embarrassed to reveal their experiences.

Both reporting methods have their strengths and weaknesses, and both are in need of improvement. The UCR remains the standard measure of criminal activity but cannot control any lack of police cooperation or the failure of victims to report crimes. The NCVS might be far more useful for compiling data in rural communities, but the results are often less accurate.

There are at least two areas of concentration that might improve the overall reporting system. Government agencies might focus more on an effort to use the UCR and NCVS in combination with one another, thereby giving law enforcement a broader, more accurate analysis. In addition, despite budget considerations, critics argue that reporting by local law enforcement agencies should be mandatory.

This is a great question, as we often hear these different terms in the news. Let's start by defining what each is.

The Uniform Crime Report is overseen by the Federal Bureau of Investigation (FBI) and is comprised of data from nearly 20,000 city, federal, county, and state law enforcement agencies, according to the FBI website. Note here that the UCR then is made up of crime data from law enforcement agencies.

The National Crime Victimization Survey relies on data collected from households, as the name implies. It is overseen by the Bureau of Justice Statistics.

With any data collection, it is going to be impossible to collect data on every single crime committed. There are a few ways we could make the data more reliable. First, while nearly 20,000 agencies is not comprehensive, it is still a large amount of data. We can take the data from the UCR and compare it to the National Crime Victimization Survey to judge the accuracy of both.

Second, both reports could benefit by trying to be comprehensive, at least on a smaller scale. For example, the Uniform Crime Report could pick 2 or 3 states and ensure that every single law enforcement agency in those states reports data. The National Crime Victimization Survey could undertake a similar effort by conducting a census-like survey of major cities as well.

Both the Uniform Crime Reports (UCR) and the National Crime Victimization Survey (NCVS) were designed to gather and report on the United State's national crime rates. While both have their limitations and therefore inaccuracies, one difference between the UCR and NCVS is that NCVS is far more likely to be inaccurate due to its methods of collecting data.

The UCR is a cooperative effort for nation-wide law enforcement agencies to report on national crime statistics. According to the FBI's "Summary of the Uniform Crime Reporting Program," every month, "18,000 city, university and college, county, state, tribal, and federal law enforcement agencies voluntarily [report] data on crimes brought to their attention" (as cited in "Uniform Crime Reports"). The UCR first began in the 1920s and 30s. By 1930, the Federal Bureau of Investigations (FBI) was made responsible for compiling the data, though the FBI does not and has never collected the crime statistic data itself. The UCR divides crimes into two major categories called Part I offenses and Part II offenses. Part I reports data on "violent and property crimes" ("Uniform Crime Reports"). The list of crimes included under the violent crime classification are "aggravated assault, forcible rape, and robbery" ("Uniform Crime Reports"). The list of crimes classified under property crimes include "arson, burglary, larceny-theft, and motor vehicle theft" ("Uniform Crime Reports"). Part II reports on crime categories like "simple assault, curfew offenses and loitering, embezzlement, forgery and counterfeiting, disorderly conduct, driving under the influence, drug offenses, fraud, gambling, liquor offenses, offenses against the family, prostitution, public drunkenness, runaways, sex offenses, stolen property, vandalism, vagrancy, and weapons offenses" ("Uniform Crime Reports"). Since the UCR is composed of data reported monthly by law enforcement agencies, it is the most accurate crime statistics report we have; however, one of its weaknesses is that reporting crime statistics data for the UCR is not mandatory for all state law enforcement agencies. Therefore, some of the crime statistics may be "under-reported" ("Uniform Crime Reports"). A second weakness is that the crimes reported are only what the police have noted or made arrests for and not the crimes that have been sentenced at the judicial level.

In contrast to the UCR, the NCVS is merely a crime report conducted by the Bureau of Justice Statistics through surveys under the United States Census Bureau. The surveys include only 49,000 to 77,400 households two times a year. The United States Census Bureau chooses a random cluster of households to interview concerning violent crimes and continues to survey the household sample for three years, following up with more interviews every six months. The types of violent crimes that the surveys gather statics on include "assault, burglary, larceny, motor vehicle theft, rape, and robbery," as well as domestic violence ("National Crime Victimization Survey"). However, critics of the NCVS argue that the data is unreliable, especially when it comes to domestic violence, because only the "entire selected household is interviewed" rather than interviewing individual people ("National Crime Victimization Survey"). Individual people are more likely to be honest about domestic violence than heads of the household. The data is further unreliable in comparison with the URC because only a select few households are interviewed, whereas the URC attempts to be a report of all crime statistics.