Brief State and Trait Happiness Scales: Validation and Work Arrangement Differences in Thai Workers

Background: This study aimed to develop and validate brief measures of state (CUHI-S-SF) and trait (CUHI-T-SF) happiness derived from the Chulalongkorn University Happiness Inventory and to examine differences in happiness and psychological distress across work arrangements among Thai working adults. Methods: A cross-sectional online survey collected data from 452 participants using convenience sampling. Exploratory factor analysis (EFA) was conducted with Sample I (n ¼ 250; Mage ¼ 33.04) to examine internal structure, followed by confirmatory factor analysis with Sample II (n ¼ 202; Mage ¼ 35.29). Independent-samples t tests compared on-site and non—on-site workers on happiness and psychological distress. Results: EFA supported a five-item unidimensional structure for the CUHI-S-SF and a nine-item three-factor structure (Positive Thinking, Gratitude, Pessimism) for the CUHI-T-SF, explaining 68% and 71% of the variance. CFA demonstrated good model fit, with all factor loadings >0.50 and Cronbach's α values of 0.84 (CUHI-S-SF) and 0.83 (CUHI-SSF). Convergent validity was supported by positive correlations with happiness and well-being, all p < 0.001. Both short forms correlated strongly with their full versions (r ¼ 0.89—0.92). Group comparisons showed no significant differences in state happiness, stress, anxiety, or depression, but on-site workers reported significantly higher trait happiness, t(200) ¼ 3.53, p < 0.001, d ¼ ¡0.51. Conclusion: The CUHI-S-SF and CUHI-T-SF demonstrate good psychometric properties and serve as efficient tools for assessing happiness among Thai working adults. Findings indicate that only trait happiness varies across work arrangements.