Sample پرسشنامه بار کاری NASA-TLX

What does the NASA-TLX measure?

The subjective workload of a specific task, right after doing it, on six dimensions: mental demand, physical demand, temporal demand, performance, effort and frustration. It was built for aviation and is now used in ergonomics, healthcare, driving and software usability testing.

Number of items

6

Time to complete

1–2 minutes per task

Score range

0 to 100

Reversed items

None

Response scale

A 0–100 scale in steps of 5 (the 21 marks of NASA's sheet); five dimensions run from "very low" to "very high" and performance from "perfect" to "failure"

Authors

Sandra Hart (NASA Ames Research Center) and Lowell Staveland, 1988

Scoring the NASA-TLX

1. 1.Each dimension is a number from 0 to 100 in steps of 5. On performance the "failure" end is the high number, so on all six dimensions a higher number means more workload and nothing is reversed.
2. 2.This template calculates the Raw TLX: the simple mean of the six dimensions, with no weighting.
3. 3.Hart and Staveland's original method adds 15 pairwise comparisons before averaging: each dimension's weight is the number of times it was chosen as more important (0–5), and the score is the sum of rating × weight divided by 15. That step is not in the template; if you need it, add 15 single-choice questions and a calculated field, and state in your report which version you used.
4. 4.The "largest source of workload" field names the dimension with the highest rating (on a tie, the first dimension in form order).
5. 5.Fill it in for each task separately and right after the task; for several tasks add a "task name" question or build one form per task.

Interpreting NASA-TLX scores

NASA set no cut-offs or low/high ranges for the TLX score. Interpret it comparatively — between tasks, designs or groups, for example before and after redesigning a process — and look at each dimension too.

NASA-TLX validity and reliability

• Hart and Staveland (1988) analysed subjective ratings of 10 workload-related factors across 16 experiments — from simple cognitive and manual tasks to flight simulation — and selected the six TLX dimensions from them.
• Hart (2006) reviewed 550 studies that had used or examined the NASA-TLX over 20 years; its use has spread far beyond aviation and English.
• In published comparisons the raw version has been sometimes more, sometimes equally and sometimes less sensitive than the weighted version.

Source and translation

Original instrument: Sandra Hart (NASA Ames Research Center) and Lowell Staveland, 1988

• 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 (Advances in Psychology, Vol. 52, pp. 139–183). 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.

The NASA-TLX was developed by NASA (a US government agency), which describes it as open source; according to NASA no permission is needed to use or modify it, including translating it.

Translated by Porsino; for formal research, cite a validated (normed) Persian version.