Many different government and nongovernmental entities collect information about the use and abuse of different types of drugs, resulting in a wealth of information on these topics but creating difficulties for the researcher because there is no single clearinghouse where all this data may be accessed. In addition, due to differences in sampling, questionnaire construction, and other specifics of the data collection process, surveys conducted within the same country or region may produce quite different estimates of, for instance, the rate of marijuana use or binge drinking within a particular segment of the population or overall. This entry will concentrate on data sets collected within the United States, but similar information often exists for other countries or regions. For instance, the European Monitoring Centre for ...