The major objectives of the two projects cited are to develop and improve techniques for prevalence estimation, thereby increasing the accuracy of the estimates; to apply these techniques to derive prevalence estimates for cocaine use among general and criminal justice populations; and to examine the applicability of these models for policy analysis. This report includes program codes for the models developed. The study applied three estimation methodologies: synthetic estimation, multiple-capture census, and system dynamics. Results from applications of multiple estimation models can provide more than enumeration of drug users; such estimation reveals inadequate treatment capacity and low utilization of treatment services among some groups, especially among criminal justice populations. Model projections show that expanded treatment programs may be more effective than drug interdiction in stemming the use of cocaine. Incarceration for drug law offenses is noted as an expensive but similarly effective intervention. Highest confidence in estimation is achieved when multimethod approaches complement each other and compensate for database inadequacies and inherent flaws in single-method approaches. Figures, appendixes (noted in Table of Contents but not in document)