The vast majority of crimes come to the attention of the police in response to citizen complaints. citizens do not usually bother to inform the authorities if they do not think a crime is serious enough or feel that nothing can be done. this means that there might be serious bias in the

   Uniform Crime Report

Explanation:  It is, in fact, the FBI's program of voluntary reporting of crime, so-called Uniform Crime Reporting (UCR), which is implemented nationwide, involving all local, city communities, colleges, colleges, agencies, etc. The goal of this program, which has existed since the 1930's, is to collect information widely and to generate it as a reliable source for law enforcement purposes. If in this case, citizens do not bother to report the crimes because they think they are not serious, or the citizens themselves assess whether they will report the crime or not and for which they are not competent, there may be a bias in Uniform Crime Report.