National Drug Threat Survey (NDTS) Data Uses

Maps depicting NDTS data are designed to show patterns of responses based on the geographic location of the responding agencies.  Unlike the weighted statistical estimates discussed below, NDTS data maps are not weighted and are not representative of a given state, region, or the United States as whole – rather, they are intended to provide an overall visual pattern of the data.

   

Data collected through the NDTS are used to produce statistical estimates that are representative at the national, regional, and state levels.  Based on responses received from law enforcement agencies in the NDTS sample, weighted estimates for the population of all law enforcement agencies (as defined in the sampling frame) are derived for each survey question at the national, regional, and state levels.  Although stratified to include large-scale law enforcement agencies (based on the number of Full Time Equivalent sworn officers), the NDTS sample is not weighted directly to the population in the jurisdictional areas of sample agencies.

The error of estimation for NDTS percentages as reported in graphs and data tables is close to 5 percent.  This level of error should be taken into consideration when interpreting percentages or differences between percentages of reported NDTS estimates.