NASA-TLX — Task Load Index (RTLX)
A subjective workload index that measures how demanding a task feels across six dimensions — complementing the physical methods for mentally demanding work.
What is NASA-TLX?
NASA-TLX is the most widely used subjective workload instrument. Ergocure uses the Raw TLX (RTLX) variant — the unweighted mean of six self-rated dimensions — which Hart's 2006 review found correlates almost perfectly with the original weighted score while being far quicker for workers to complete. It measures perceived workload, not posture, so it sits alongside the physical assessments rather than replacing them.
When to use NASA-TLX
Use NASA-TLX for cognitively demanding or high-pressure roles — control rooms, dispatch, monitoring, healthcare and emergency response — where mental workload, not posture, is the primary risk.
Primary citation: Hart, S.G. & Staveland, L.E. (1988). Development of NASA-TLX. Advances in Psychology, 52, 139–183. · Hart, S.G. (2006). NASA-TLX: 20 years later. Proc. HFES, 50(9), 904–908.
What NASA-TLX assesses
The body segments and task variables evaluated in a NASA-TLX assessment.
What it assesses
- Mental, physical and temporal demand
- Perceived performance (reverse-scored)
- Effort and frustration
Scoring and action levels
Final score range: Composite 0–100 → three tertile bands
Developed by: Hart & Staveland, 1988 (RTLX: Hart, 2006)
How Ergocure.ai applies NASA-TLX
NASA-TLX runs camera-free: the worker rates their task on six workload dimensions. Ergocure scales and averages them into a 0–100 score (reversing the performance item) and maps it to a workload band automatically, then a certified ergonomist reviews and signs off before the worker sees the result.
Captured on any phone, scored for NASA-TLX, and validated by a certified ergonomist — face-blurred on-device.
NASA-TLX — frequently asked questions
What is NASA-TLX (Task Load Index (RTLX))?
A subjective workload index that measures how demanding a task feels across six dimensions — complementing the physical methods for mentally demanding work.
What is a good NASA-TLX score?
Composite 0–100 → three tertile bands. A score of 0–33 is low — workload within comfortable range — while 67–100 is high and means reduce demand or add recovery.
When should you use NASA-TLX?
Use NASA-TLX for cognitively demanding or high-pressure roles — control rooms, dispatch, monitoring, healthcare and emergency response — where mental workload, not posture, is the primary risk.
How does Ergocure score NASA-TLX?
NASA-TLX runs camera-free: the worker rates their task on six workload dimensions. Ergocure scales and averages them into a 0–100 score (reversing the performance item) and maps it to a workload band automatically, then a certified ergonomist reviews and signs off before the worker sees the result.
Who developed NASA-TLX?
NASA-TLX was developed by Hart & Staveland, 1988 (RTLX: Hart, 2006). Hart, S.G. & Staveland, L.E. (1988). Development of NASA-TLX. Advances in Psychology, 52, 139–183. · Hart, S.G. (2006). NASA-TLX: 20 years later. Proc. HFES, 50(9), 904–908.
Related assessment methods
Methods commonly used alongside NASA-TLX in a complete ergonomic assessment.
See NASA-TLX in a live assessment
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