NASA-Task Load Index in CHI: A Comprehensive Review and Subscale Meta-Analysis with Implementation Guidelines

The NASA-Task Load Index (NASA-TLX) is a widely used multidimensional scale for measuring subjective workload in Human-Computer Interaction (HCI) research. Despite widespread adoption, diverse reporting methods hinder cross-study comparisons and standardization. We systematically reviewed 522 CHI papers (2006–2024) to identify usage variations and common implementation errors, and collected subscale values from 683 tasks across 185 papers for meta-analysis. Correlation, regression, and factor analyses revealed stronger inter-subscale correlations than the original development study, different beta weights, and weakened discriminability. Factor analysis identified a two-factor structure, with Performance showing notably low communality as a distinct dimension. We propose a Short TLX (STLX) that retains Mental Demand , Physical Demand , and Performance as a condensed instrument, given that many studies already omit subscales. We provide standardized implementation guidelines and contribute an interactive research database and a data collection toolkit to facilitate consistent use of NASA-TLX across the HCI community.