THE BUREAU OF RESEARCH OF THE NEW YORK STATE OFFICE OF DRUG ABUSE SERVICES HAS EMBARKED ON A PILOT INVESTIGATION CALLED 'THE EPIDEMIOLOGICAL MONITORING STATIONS PROJECT.' THE PURPOSE OF THE PROJECT IS TO DETERMINE THE FEASIBILITY OF ESTABLISHING AN INFORMATION SYSTEM TO MONITOR THE USE OF DRUGS IN THE STATE BY MEANS OF UNOBTRUSIVE TECHNIQUES INSTEAD OF SURVEYS. FACTORS CONSIDERED INDICATORS OF DRUG ABUSE WERE MONITORED IN FOUR COUNTIES VARYING FROM URBAN TO RURAL--WESTCHESTER, RENNSSELAER, TOMPKINS, AND COLUMBIA. INFORMATION RECORDED IN THE CRIMINAL JUSTICE SYSTEM, THE HEALTH DELIVERY SERVICES SYSTEM, AND THE TREATMENT AND REHABILITATION SYSTEM IS BEING MONITORED TO SEE IF THE ITEMS OF INFORMATION CORRELATE WITH DRUG USE IN THE COUNTIES. ARREST DATA WERE GATHERED FROM THE COUNTIES FOR THE YEARS 1973 THROUGH 1975. A DRUG ARREST WAS DEFINED AS AN ARREST INCLUDING AT LEAST ONE DRUG CHARGE, REGARDLESS OF SEVERITY. FOR THE YEARS FOR WHICH DATA WERE GATHERED, DRUG ARRESTS UNIVERSALLY DECLINED AND NONDRUG ARRESTS UNIVERSALLY ROSE. IN ASSESSING THE VALUE OF DRUG ARREST DATA FOR MEASURING THE EXTENT OF DRUG ABUSE, TWO DRAWBACKS ARE NOTED: (1) RECORDS OF ARRESTS OF COUNTY RESIDENTS OCCURRING OUTSIDE THE COUNTY ARE NOT RETRIEVED BY THE DATA COLLECTION METHODS AVAILABLE; AND (2) TWO POLAR MODELS OF DATA ANALYSIS CAN BE USED--ARREST DATA AS AN INDICATOR OF ACTUAL DRUG USE AND ARREST DATA AS AN INDICATOR OF PRIORITIES FOR POLICE ACTIVITY. GIVEN THE LIMITATIONS OF INTERPRETATION IMPOSED ON ARREST DATA USED IN ISOLATION, IT IS CONCLUDED THAT IT MUST BE USED IN TRIANGULATION WITH DATA ON OTHER INDICATORS BEFORE THE EXTENT OF DRUG USE IN A GIVEN AREA CAN BE REASONABLY ESTIMATED. SUMMARY DATA FROM THE STUDY ARE REPORTED. (RCB)