DATA CONCERNING THE IMPACT OF CRIME ON ALARM USERS AS COMPARED WITH NONALARM USERS WERE COLLECTED FROM POLICE REPORTS, PERMIT FILES, AND PERSONAL INTERVIEWS IN MULTNOMAH COUNTY, OREG. ALTHOUGH AVERAGE DOLLAR LOSSES AND ARREST RATES FOR BOTH GROUPS WERE SIMILAR, FURTHER STUDY SHOWED THAT POLICE SPENT CONSIDERABLY MORE INVESTIGATIVE TIME WITH NONUSER VICTIMS, AND THAT CERTAIN TYPES OF ALARM SYSTEMS LOWERED DOLLAR LOSS. ALARMED RESIDENCES AND COMMERCIAL PROPERTIES EXPERIENCED A SIGNIFICANTLY LOWER RATE OF ROBBERY AND BURGLARY THAN THOSE WITHOUT ALARM SYSTEMS. DIFFERENT TYPES OF ALARMS WERE RATED FOR EFFECTIVENESS BASED ON POLICE RECORDS, UNDERWRITER LABORATORY CERTIFICATIONS, AND COMPARISONS OF ALARM MANUFACTURERS AND MONITORING SERVICES. IN GENERAL, THE SILENT BURGLAR AND COMBINATION BURGLAR ALARMS APPEARED TO BE THE MOST EFFECTIVE. TO EVALUATE PROBLEMS CAUSED BY FALSE ALARMS, METHODS FOR MEASURING THE FALSE ALARM RATE WERE DEVELOPED, AND SYSTEMS WERE RANKED FOR FALSE ALARMS ACCORDING TO TYPE, MANUFACTURER, AND MONITORING SERVICE. FALSE ALARMS WERE FOUND TO BE A DRAIN ON POLICE RESOURCES IN TERMS OF COST AND UNNECESSARY DIVERSION OF MANPOWER. SINCE USER ERROR APPEARS TO BE A MAJOR CAUSE OF FALSE ALARMS, INCREASED RESPONSIBILITY BY ALARM OWNERS COULD HELP TO ALLEVIATE THE PROBLEM. OVERALL, ALARM SYSTEMS WERE JUDGED TO BE VERY EFFECTIVE IN DETERRING AND REDUCING CRIME. INCREASED COOPERATION BETWEEN LAW ENFORCEMENT AGENCIES AND THE ALARM INDUSTRY WAS RECOMMENDED TO IMPROVE ALARM SYSTEMS AND REDUCE FALSE ALARMS. THE APPENDIXES INCLUDE DETAILED VICTIMIZATION DATA; COMPARISONS OF ALARM COMPANIES, MONITORING SERVICES, AND ALARM TYPES; FALSE ALARM RANKINGS OF SYSTEMS; AND INFORMATION ON THE INCIDENCE AND COST OF FALSE ALARMS. (MJM)