The Accuracy of Evaluations by Drug Recognition Experts in Canada

The objective of this paper is to illustrate the accuracy with which police officers trained as Drug Recognition Experts (DREs) can identify the category of drug(s) ingested by persons suspected of being impaired as the result of drug use. The study examined 1,349 drug evaluations completed by DREs in Canada to determine the extent to which DRE opinions about the category of drug(s) used matched the results of toxicological analysis of fluid samples. The paper presents measures of sensitivity, specificity, the false alarm rate, and miss rate for all drug categories combined as well as for the most commonly found substances. The data demonstrate that the drug evaluations conducted by DREs in Canada are accurate.