PEBL Hub — IRB Fact Sheet — 2026-08-23
NASA Task Load Index (TLX)
Category:Personality & Rating Scales
Duration:~2 minutes
Parameters:3 configurable parameters: weightings toggle, task name, and scale height
Version:1.0
Input:Mouse, Touch
Description
A multidimensional assessment tool for measuring subjective workload across six dimensions
The NASA Task Load Index (TLX) is a widely-used multidimensional assessment tool that provides an overall workload score based on a weighted average of ratings on six subscales: Mental Demand, Physical Demand, Temporal Demand, Performance, Effort, and Frustration. The standard TLX includes optional pairwise comparisons to weight the dimensions, though weights are often omitted in practice. This implementation presents each dimension on a visual analog scale and records both ratings and response times. The task name can be customized to reference the activity being rated.
Key Parameters
| doweightings | Should you do the weightings as well as the ratings? (default: 0) |
| taskname | Name of the task at the top of the screen. (default: Target Task) |
| scaleheight | Height in pixels of the scale. (default: 300) |
Example Data Output (1 sample rows)
| TASK | timestamp | subnum | taskname | w1 | w2 | w3 | w4 | w5 | w6 | s1 | s2 | s3 | s4 | s5 | s6 | time |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PEBL-TLX | Sun Nov 2 22:09:45 2025 | 15115 | Target task | 2 | 2 | 3 | 3 | 4 | 1 | 8 | 14 | 15 | 8 | 5 | 16 | 30636 |
References
Hart, S. G., & Staveland, L. E. (1988). Development of NASA-TLX (Task Load Index): Results of empirical and theoretical research. In P. A. Hancock & N. Meshkati (Eds.), Human Mental Workload (pp. 139-183). Amsterdam: North-Holland.
Hart, S. G. (2006). NASA-Task Load Index (NASA-TLX); 20 years later. Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 50(9), 904-908.