NASA Task Load Index (TLX)

NASA’s own landing page for the NASA Task Load Index (TLX), a subjective workload-assessment questionnaire.

License: Public domain — U.S. federal government work (17 U.S.C. § 105); the page itself also states the tool is “open source.”

Key points

• NASA TLX derives one overall workload score from a weighted average of ratings across six subscales: Mental Demand, Physical Demand, Temporal Demand, Performance, Effort, and Frustration.
• Originally built as a paper-and-pencil questionnaire at NASA Ames Research Center in the 1980s, it has since become described as the standard subjective-workload measure across a wide range of applications.
• Deployed to assess workload in aircraft cockpits; command, control, and communication workstations; supervisory and process-control settings; and simulations and laboratory tests.
• No permission from NASA is required to use, redistribute, or modify the tool (including translating it into another language).
• Available as the original paper-and-pencil form (paired with an instruction manual and pairwise-comparison cards) or as an iOS app for iPhone, iPad, and iPod touch.

Cited In

Processes

• NASA-TLX