One of the most glaring gaps in available data involves the simple tabulation of offenses committed by juveniles. Uniform Crime Reports (UCR) offenses data do not distinguish crimes committed by juveniles from those committed by adults. UCR arrest data also are a limited source of information on juveniles apprehended by police, since police agencies must decide what level of contact with a minor constitutes an "arrest." Statewide prosecution and court case data pertaining to juvenile offenders also have some significant gaps. The most detailed statistics on juvenile offenders pertain to their detention and incarceration. The Juvenile Monitoring Information System contains case-level information on minors placed in juvenile detention centers and in county jails in Illinois. A relatively unexplored source of information on juvenile offenders in Illinois is the Illinois State Police's Computerized Criminal History (CCH) system. This system collects individual case-level data on criminal offenders from law enforcement, prosecution, courts, and corrections and comes closest to the concept of an offender-based tracking system. The Illinois Criminal Justice Information Authority and the Illinois State Police are working together on several initiatives that are expected to improve the quality of criminal history records.