Final answer:
The two principal systems used to measure crime in the United States are the UCR and NCVS. The dark figure of crime refers to unreported or undetected crimes.
Step-by-step explanation:
In the United States, there are two principal systems used to measure crime: the Uniform Crime Reports (UCR) and the National Crime Victimization Survey (NCVS).
The UCR is collected by the FBI and gathers data from approximately 17,000 law enforcement agencies. It provides comprehensive information from police reports but fails to account for unreported crimes. The NCVS, on the other hand, is a survey conducted by the Bureau of Justice Statistics and collects data directly from households. It captures both reported and unreported crimes, providing a more accurate picture of crime.
The concept of the dark figure of crime refers to the gap between the actual amount of crime that occurs and the amount of crime that is reported or recorded. It represents the crimes that go unreported or undetected by the criminal justice system. This concept highlights the limitations of relying solely on reported crime data and the need to consider unreported crimes when analyzing crime rates and trends.