Comparing and contrasting the effectiveness of time-space sampling methods to identify club drug using emerging adults

Time-space sampling has been used to generate representative samples of hard-to-reach populations.

Methods. In an effort to identify club drug use among club-going emerging adults (ages 18-29) in the NYC nightlife scene, two variations of time-space sampling methods were utilized (Version 1: Randomized venue, day of week, and individuals within-venues. Version 2: Randomized venue and day only). An exhaustive list of nightlife venues were enumerated and randomized. Survey teams approached potential participants as they were entering or exiting venues to conduct brief anonymous surveys.

Results. Over the course of 24 months, 14,366 approaches were conducted (n_v1 = 4,135, n_v2 = 10,231) resulting in 10,678 consenting to participate (V1 response rate = 46.0%, V2 response rate = 85.8%). Individuals screened during Version 1 were statistically older (M_v1 = 24.40, SD_v1 = 2.81; M_v2 = 23.78, SD_v2 = 2.86), but equally likely to report having ever used a drug (68.9%). There were significant differences by sampling strategy for prevalence of MDMA (V1 = 45.2%, V2 = 56%), Cocaine (V1 = 41.0%, V2 = 50.7%), and LSD (V1 = 25.5%, V2 = 30.6%), but not for Ketamine (21.8%), GHB (11.0%), or Methamphetamine (14.6%).

Conclusion. Time-space sampling is an effective strategy to quickly detect and screen club drug users; however, caution is urged in how this methodology is implemented. The second version of implementation improved response rate and seemed to more effectively identify individuals having used MDMA, Cocaine, and LSD.