Cross-cultural adaptation and validation of the Traditional Chinese NASA Task Load Index (NASA-TLX) for assessing perceived workload in Taiwanese adults

Abstract

Background Perceived workload is central to occupational health, ergonomics, and rehabilitation research, yet no guideline-based Traditional Chinese version of the NASA Task Load Index (NASA-TLX) has been available for Taiwan and other Traditional-Chinese-speaking settings. Objective To cross-culturally adapt the NASA-TLX into Traditional Chinese (NASA-TLX-TC) and evaluate its measurement properties in Taiwanese adults. Methods In a psychometric secondary analysis, 114 community-dwelling adults aged 20–50 years completed the NASA-TLX-TC on three consecutive days. Within the COSMIN framework, we examined content validity, internal consistency, structural validity (exploratory factor analysis with parallel analysis), test-retest reliability (intraclass correlation [ICC]), measurement error, and construct validity (seven a priori hypotheses involving sleep, mood, and shift work). Results The content validity index averaged 0.88 and Cronbach's α was 0.83. The six dimensions loaded on a single factor (55.8% of variance). The three-day average score showed good reliability (ICC[A,k] = 0.83), whereas single-day reliability was moderate (0.62); the minimal detectable change was 32 points. Six of seven construct-validity hypotheses were supported; the shift-work difference was in the predicted direction but nonsignificant. Internal consistency and convergent validity were stable across subgroups. Conclusions The NASA-TLX-TC showed good reliability and initial construct validity and is suitable for group-level occupational-health, ergonomics, and rehabilitation research; multi-day averaging is recommended for individual assessment.