THEY ARE A (1) MESSAGE SWITCHING AND STATISTICAL ACCOUNTING CAD SYSTEM, AND (2) THE FULLY OPERATIONAL SUPPORT CAD SYSTEM. THE FORMER SYSTEM CAN BE RELATIVELY INEXPENSIVE AND IS DRIVEN BY A MINICOMPUTER. IT RAPIDLY TRANSFERS DATA WITHIN A COMMUNICATIONS CENTER, AND RECORDS AND COMPILES AN INDIVIDUAL'S OR GROUP'S ACTIVITIES AND PRODUCTIVITY IN VARIOUS WAYS. ALTHOUGH MESSAGE-ACCOUNTING SYSTEMS PRODUCE USEFUL STATISTICS, THEY ARE BEST SUITED FOR SMALL DEPARTMENTS POLICING SMALL, WELL-DEFINED AREAS. FULLY OPERATIONAL CADS ALSO PROVIDE GEOGRAPHICAL DATA. THEY CAN IDENTIFY BEATS FROM ADDRESSES, PLOT INCIDENTS AND CALLS FOR SERVICE GEOGRAPHICALLY, RECOMMEND THE NEAREST AVAILABLE PATROLS, AND PROVIDE ON-LINE RECALL OF INCIDENTS. SUCH SYSTEMS ARE MORE EXPENSIVE AND BEST FOR MEDIUM OR LARGE POLICE DEPARTMENTS. BOTH TYPES OF CADS IMPROVE PRODUCTIVITY AND RESOURCE MANAGEMENT. THEY CAN PROVIDE DATA AIDING OFFICERS' SAFETY AND INVESTIGATIONS, ESPECIALLY THROUGH CAD INTERFACE WITH OTHER DATA BANKS. CADS CAN ALSO PROVIDE POLICE MANAGERS WITH A WIDE VARIETY OF DATA ON OFFICERS AND CRIME PATTERNS. PROBLEMS WITH CADS INCLUDE DISRUPTIONS IN POLICE WORK WHEN THE COMPUTER IS DOWN, INTERFERENCE IN POLICE WORK BY COMPUTER SPECIALISTS, LOSS OF ASSIGNMENT FLEXIBILITY, AND INCREASED EQUIPMENT COSTS AS COMPUTERS BECOME OBSOLETE. (PAP)