NASA TLX Task Load Index - Evaluation Program (Workload.exe). Version 2.2: User Guide


  1. Dufort, P.
  2. Reid, L.
Corporate Authors
Defence R&D Canada - Toronto, Toronto ONT (CAN);Toronto Univ, Toronto ONT (CAN) Inst for Aerospace Studies
The NASA Task Load Index (TLX) provides a standard and widely used protocol for assessing a subject's perceptions of the difficulty they experienced while performing experimental tasks. The index is defined in terms of six rating scales that decompose the difficulty subjects experienced along different psychological axes. The TLX protocol as originally developed called for a paper-and-pencil evaluation to collect the information necessary for computation of the index. A more convenient DOS-based program written in Turbo Pascal automated the original version, providing a simple user interface. This guide describes a new implementation of this software, designed to run under recent version of the Microsoft Windows (TRADEMARK) operating systems, augmented with several new features to help organize and simplify the collection of TLX data. Data may be saved to a comma-separated variable text file for further processing. Three additional optional rating scales may be selected to provide greater diagnostic assessment than that available from the original method. These scales include ratings for the Visual and Auditory demands as well as an overall workload perception. The program is functional but should still be considered under development. TRUNCATED
Cognitive task analysis;Human engineering;Mental workloads
Report Number
DRDC-TORONTO-CR-2002-123 — Contractor Report
Date of publication
11 Jul 2002
Number of Pages
Hardcopy;Document Image stored on Optical Disk

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