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Glossaries

Task Load Index

What is Task Load Index (TLX)?

Task Load Index (TLX) is a subjective, multidimensional assessment tool used in user research to measure the perceived workload of completing a specific task. It evaluates six different factors: mental demand, physical demand, temporal demand, performance, effort, and frustration level.

Synonyms: NASA-TLX, Workload Assessment, Cognitive Load Measurement, User Task Evaluation

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How Task Load Index (TLX) is Used in User Research

Task Load Index (TLX) is a valuable tool in user research for assessing the cognitive and physical demands of various tasks. Researchers use TLX to:

  1. Evaluate interface designs
  2. Compare different versions of a product
  3. Identify areas of high workload in user interactions
  4. Optimize task allocation in complex systems

By understanding the perceived workload, designers can create more user-friendly and efficient interfaces.

Benefits of Using Task Load Index (TLX)

Implementing TLX in user research offers several advantages:

  1. Quantifiable results: TLX provides numerical scores that can be easily compared and analyzed.
  2. Multidimensional assessment: It considers various aspects of workload, giving a comprehensive view of user experience.
  3. Versatility: TLX can be applied to a wide range of tasks and industries.
  4. Validated methodology: As a well-established tool, TLX has been extensively tested and validated in numerous studies.

How to Conduct a Task Load Index (TLX) Assessment

To use TLX in your user research:

  1. Have participants complete the task you want to evaluate.
  2. Immediately after task completion, ask participants to rate each of the six factors on a scale (usually 0-100 or 0-20).
  3. Optionally, have participants weigh the importance of each factor.
  4. Calculate the overall workload score by combining the ratings and weights (if used).
  5. Analyze the results to identify areas of high workload or potential improvements.

Frequently Asked Questions

  • What are the six factors measured in Task Load Index (TLX)? The six factors are mental demand, physical demand, temporal demand, performance, effort, and frustration level.

  • Is Task Load Index (TLX) only used in software user research? No, TLX can be used in various fields, including aviation, healthcare, and manufacturing, to assess task workload.

  • How long does it take to complete a Task Load Index (TLX) assessment? The assessment itself is relatively quick, usually taking 5-10 minutes to complete after the task is finished.

  • Can Task Load Index (TLX) be used for remote user testing? Yes, TLX can be adapted for remote testing by using online forms or specialized user research tools.

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