Abstract
Knowledge of drug use patterns is necessary for policy formulation and implementation, especially in terms of law enforcement strategies, treatment, and educational programs. Unfortunately it is usually impossible to accurately assess the overall extent of drug use and abuse. Instead, data are collected from a variety of sources to provide estimates used in policy planning. In this paper drug-related data from three sources are compared to determine similarities and differences in drug use among three population groups: those who come into contact with law enforcement agencies, high school students, and those enrolled in treatment programs. The uses of these data for policy and program planning are suggested.