Public funds are viewed has having been invested to improve the knowledge base of drug prevention and treatment, but not to learn about drug law enforcement. The chairman of the National Research Council (NRC) Committee on Data and Research for Policy on Illegal Drugs presents commentary which surmises reasons for the distressing status quo and recommends changes in research practices that may improve the investment in and credibility of research on drug law enforcement. The commentary begins with a retrospective on two studies by RAND and the Institute for Defense Analyses (IDA), of cocaine control policy which led to the NRC undertaking a broad search for other research that could inform cocaine policy, with little results. The NRC committee concluded that neither the RAND nor the IDA study provided a credible estimate of what it would cost to use alternative policies to reduce cocaine consumption in the United States. Two complementary ways are discussed to improve the credibility of research on drug law enforcement and other controversial policy questions: (1) enrich the available data in order to lessen the dependence of research on unsubstantiated conjectures and (2) promote due caution in policy research in areas, such as missing data and counterfactuals. References