Factors influencing field performance: utilizing the drug evaluation and classificaiton (DEC) program to identify suspected impaired drivers as reported by selected certified police officers in Texas

This study examined how decision-making training related to the Drug Evaluation and Classification (DEC) Program was transferred to law enforcement officers, referred to as drug recognition experts (DRE), for use in identifying and assessing impaired drivers. Specifically, this study explored how particular factors observed as part of the DEC Program’s decision-making process influence the DRE’s prediction of a drug category that was impairing a suspected impaired driver in the enforcement environment. Quantitative and qualitative methods were utilized to better understand the complexity of the DRE’s decision-making. Factors observed from 199 drug influence evaluations (DIE) were used as a basis for the quantitative analysis. In addition, feedback gleaned from the interviews conducted with six DREs was analyzed to identify themes that described the perceptive influence of those same factors on the DRE’s prediction of a drug category. The DREs classified 88.4% of the DIEs correctly when compared to the toxicology results according to the criteria set-forth in the DEC Program’s Administrator’s Guide. The accuracy rates at the drug category level were 82.9% for Depressants and Cannabis, 80.9% for Stimulants, 96.5% for Dissociative Anesthetics, and 81.9% for Narcotic Analgesics. The results of the study showed that the DREs employed their DEC Program training appropriately, but reportedly used a subset of factors as a basis for their predictions. The quantitative analysis indicated that the factors the DRE expected to observe when a particular drug category was present in the toxicology results were documented as present on the DIE report by the DRE. In contrast, only a subset of those factors was unique to that drug category. The qualitative feedback from the DREs indicated that they rely on a subgroup of factors, such as those related to the eyes, as the main basis for their decision-making. The DREs also emphasized their consideration of the totality of evidence as major driver in their decision-making. The DEC Program provided an interesting opportunity to explore the transfer of decision-making training. Based on the results of this study, the DEC Program can improve the transfer of training by targeting DRE’s motivation to transfer training into practice, the transfer design, and the climate in which the DRE transfers their learning into performance.