Objective: The Timeline Follow-back (TLFB) questionnaire has become a pre-eminent tool in substance use and human immunodeficiency virus (HIV) risk research, allowing researchers to assess fine-grained changes in risk behavior over long periods. However, data on accuracy of recall over long (12-month) periods are sparse, especially combined data on HIV risk and substance use from post-treatment samples. Studies on the development of substance use and HIV risk stand to benefit from data on the accurate recall of such behavior over longer retroactive spans of time.
Method: The present study offers data on the test-retest reliability of current TLFB assessment versus 6- and 12-month delayed TLFB assessment, using a post-treatment sample (n = 50).
Results: Long-term reliability of TLFB data on HIV risk was predominantly good to excellent, with 13 of 20 assessed variables in that range. TLFB data on substance use was similar, with 22 of 26 variables resulting in good/excellent reliability.
Conclusions: Our findings support the notion that, notable exceptions aside, the TLFB may be effectively used to assess retroactive HIV risk and substance use in periods of 12 months.