2.4: Main Criminal Justice Data Sets

Main Criminal Justice Data Sets

In the field of criminal justice, we tend to rely on one or more of three main data sets for most of our information and studies. Because we rely so heavily on these data sets that it is important to understand both their strengths and weaknesses.

Uniform Crime Reports (UCR)

The UCR is the best-known source of official crime statistics. The collection of this information began in 1930 by the International Association of Chiefs of Police (IACP). It is broken into two main parts. Part I contains information on eight main crimes which are thought serious enough and widespread enough to accurately measure. The eight main crimes include homicide, rape, robbery, assault, burglary, larceny (theft), motor vehicle theft, and arson. The first four are considered violent crimes and the last four are considered property crimes. Part II contains information on all other crimes except traffic. It is typically information from only part one that is released to the public. I suspect that when you heard a number about crimes in the United States or saw the ticking clock example that is used in the news, you assumed that it was a measure of all crimes, not eight crimes. Furthermore, if you hear about the violent crime rate or of the property crime rate is actually just four out of the eight recorded crimes. This count of crimes is collected by law enforcement officers in the field based on crimes that have been reported to them. (It is of course important to note that not all crimes are reported.) Each department then forwards its information to the state headquarters who then compiles information for the state and forwards it to the Federal Bureau of Investigation (FBI) in Washington, DC. The FBI then compiles all this information and shares some of the results with the media and the public. The formula used to calculate the “crime rate” is actually quite simple but yet very important so we understand how we can compare the rate of one state to another or the rate of one country to another even though their population sizes may be quite different.

Image 2.3

Uniform Crime Reports Formula

The formula is simply the number of reported crimes, divided by the population under study, multiplied by a constant, and then reported as the rate for the constant. For instance, the FBI reports the “crime rate” by taking the total number of reported crimes, dividing it by the total US population as reported by the Census Bureau, multiplied by the constant 100,000 and then the rate is reported per 100,000 people.(number of reported crimes/total US population x 100,000 = rate per 100,000). I once asked my large lecture class how many students had reported a larceny in the past year. Twenty students said they had. So, we would use the formula like this: 20/250 x 100 = 8. Notice that the constant used (100) was smaller since we are studying a smaller population. The end result is that approximately 8 out of every 100 students experienced larceny each year.

Rate Fluctuations

There are many possible reasons why our reported crime rates seem to fluctuate from year to year. Some reasons will tie into our theory chapter such as the number of individuals in the "crime prone" age range of 18 to 25, for the rate of unemployment, or patterns of drug use. Other reasons are more disconcerting from a statistical accuracy point of view. For instance, if the sheriff is doing a good job and interacting well with his community more citizens may be willing to come forward and report crimes. At the end of the year, however, it will look like our sheriff is doing a bad job because the crime rate will appear to have risen compared to previous years, when actually it is just that more people were willing to report.

Crime Trends

There are some crime trends that remain constant from year to year and so weak in healthy and accuracy of these. For instance, consistently crime rates are highest in the West and the Southern portions of our country, crime rates rise dramatically during the summer months, males commit more crimes than females (though the female rate is increasing more rapidly), and younger individuals commit far more crimes than the elderly. The poor and minorities are often reported as committing crime at high levels compared to their proportion in the population. By knowing the crime trends we can allocate our resources more effectively to combat the problem.

Criticisms

No data set is perfect, but it is important to understand the weaknesses of the data set to have faith in certain findings. The main weakness of the UCR has already been mentioned and it is that many crimes, estimated about half the crimes, are not reported. The accuracy and completeness of these police reports may vary and there are few details other than the count of crime. Many states are upgrading their collection of statistics to the National Incident-Based Reporting System or NIBRS for short.  The NIBRS system is an expansion of the UCR and is already being used in the state of North Dakota. About 97% of all agencies voluntarily submit their crime statistics, but this means that there are some agencies, mainly rural agencies, that do not. We have also seen in the example above how different enforcement policies, such as encouraging citizen reporting, may influence the recorded crime rates as well.