Monitors are used mainly to assure that offenders comply with house arrest or home confinement conditions of release. The two types of devices are continuously signalling devices and programmed contact devices that contact the offender periodically. The use of monitors has increased substantially since a February 1987 survey of 53 programs in 21 States. Almost all private agencies and about half of all the responding programs charged fees to offenders in the monitoring program. Monitoring programs are run by correctional agencies, private monitoring service providers, and public noncorrectional agencies. Monitors are used in pretrial programs, police departments in small towns, work release programs in which offenders live at home, and for offenders who are at risk of probation or parole failure. Monitoring will probably increase. Data on recidivism rates for monitored offenders are not yet available. Whether monitors represent a meaningful form of punishment is a policy matter that should be discussed based on pragmatic experience and philosophical perspective. Photograph.