In 1999, the National Research Council’s (NRC) Committee for Data and Research for Policy on Illegal Drugs evaluated and critiqued the RAND, Drug Policy Research Center’s study on Controlling Cocaine: Supply Versus Demand Programs. The study identifies a significant effort to identify and model important elements of the market for cocaine and to formally characterize the interaction of producers and users and the process through which alternative cocaine control policies may affect consumption and prices. This report presents a detailed response to the NRC panel’s major concerns about the Controlling Cocaine report and include: (1) the RAND study assumed that the unit price of supplying cocaine decreased with the total quantity of cocaine supplied; (2) the RAND model used cocaine seizures as the primary measure of supply control activity; (3) the RAND study ignored the nonmonetary costs of dealer imprisonment; (4) subsequent research suggests that cocaine consumers respond to price changes more dramatically than assumed in the model; and (5) the RAND model used a single parameter to describe a variety of possible responses of cocaine consumers to price changes. Rand's responses to these criticisms include: (1) the model was reprogrammed to include the NRC panel’s alternative assumption; (2) the approach taken was consistent with a desire to test the effects of expanding average practice within each category of enforcement strategies which was parallel to the approach taken in the report’s analysis of treatment; (3) the model assumed that the price a dealer charges covers all costs and risks; and (4) the model actually used seven parameters to cover different intensities of use and transitions between different use states. The report is divided into four sections: (1) estimates of effects of drug treatment programs on cocaine use; (2) modeling the supply of cocaine; (3) modeling the demand for cocaine; and (4) evaluating the reliability of the model.