Online Timeline Followback

This website demonstrates the online version of the Timeline Followback, as used in the following paper (the abstract is included at the bottom of the page):
Pedersen, E. R., Grow, J., Duncan, S., Neighbors, C., & Larimer, M. E. (2012). Concurrent Validity of an Online Version of the Timeline Followback Assessment. Psychology Of Addictive Behaviors, doi:10.1037/a0027945

View the Online TLFB Feel free to enter data into this online TLFB. The data get deleted each night.

The code for this online TLFB is offered free of charge. You may copy this software, and use it however you see fit.
The code was written in the Perl programming language, and utilizies a MySQL database.

Perl source code
MySQL table schema

Contact: Joel Grow (joelg @

Study Abstract:
The Timeline Followback (TLFB) interview has been used extensively in the assessment of alcohol and other substance use. While this methodology has been validated in multiple formats for multiple behaviors, to date no systematic comparisons have been conducted between the traditional interview format and online versions. The present research employed a randomized within-subjects design to compare interview versus online-based TLFB assessments of alcohol and marijuana use among 102 college students. Participants were randomly assigned to receive either the online version first or the in-person interview format first. Participants subsequently completed the second format within 3 days. While we expected few overall differences between formats, we hypothesized that differences might emerge to the extent that participants are more comfortable and willing to answer honestly in an online format, which provides a degree of anonymity. Results were consistent with expectations in suggesting relatively few differences between the online version and the in-person version. Participants did report feeling more comfortable in completing the online version. Moreover, greater discomfort during the in-person assessment was associated with reporting more past-month marijuana use on the online assessment, but reported discomfort did not moderate differences between formats in reported alcohol consumption.