TLX for Android


NASA-TLX (Task Load Index) is a way of measuring subjective workload. It is often used in HCI research as a way of finding out the workload associated with interaction techniques, interface designs, etc. TLX is often administered as a paper-based questionnaire or completed online. To make it easier to administer the questionnaire during evaluations involving mobile phones, this project provides an Android version of the NASA-TLX tool.

This project adapts Keith Vertanen’s online implementation of TLX. Mark McGill helped greatly with the initial Android implementation of this project. Note that our version only provides “raw TLX”; there are no pairwise comparisons used to weight the subscales.

Source code

Available on Bitbucket.

Git repository:


Question responses are in the range of 5 to 100, with intermediate values in intervals of 5. A directory titled “TLX” is created in the root of the external storage of the phone. A separate subdirectory is created for each participant (e.g. the third participant’s responses are stored in “P3”). Responses are put into a CSV file.

The project is tailored towards one of my current projects so is designed to store a separate response file for each block in our study. Adapting this to meet your needs should be pretty simple.