The implementation of the calendar-driven ABCD TLFB instrument was done in JavaScript with the software packages bootstrap for design and the full calendar plugin. The server component of this tool was written in php and interfaces with our electronic data collection system (REDCap) for retrieval of enrolled participant information such as participant ID (pGUID), longitudinal event name and attempt number. The server component is also responsible for the storage of the collected information and the computation of derived scores. Source code of the application is available online in the public ABCD software repository (GitHub.com/ABCD-STUDY/timeline-followback).
