Final answer:
The main difference between the UCR and NCVS is that the UCR collects crime data reported to law enforcement, while the NCVS gathers both reported and unreported crime data through victim surveys.
Step-by-step explanation:
The difference between the Uniform Crime Reports (UCR) and the National Crime Victimization Survey (NCVS) primarily lies in their sources and types of data collected. The UCR is an official database that contains comprehensive crime data reported by law enforcement agencies; it focuses on reported crimes. On the other hand, the NCVS is a self-report survey that collects data through voluntary response methods such as questionnaires or interviews, targeting both reported and unreported crimes.
Option a) UCR focuses on reported crimes; NCVS on unreported crimes best describes the difference between UCR and NCVS. The UCR provides data from police reports which may not capture all crimes, particularly those not reported to authorities. Meanwhile, the NCVS can capture information on unreported crimes through victim interviews, also analyzing demographics such as age, race, gender, location, and income level.