METHODS: This study involved 555 scuba divers in Malaysia, and the questionnaire underwent a thorough development and validation process, including content and face validity assessments, as well as exploratory factor analysis. The validation of the knowledge domain was conducted using Item Response Theory (IRT) analysis, while awareness and practice were validated through exploratory and confirmatory factor analyses (EFA and CFA).

RESULTS: The content validity of the instrument was confirmed, with all items scoring over 80% for Item Content Validity Index (I-CVI), Scale Content Validity Index (S-CVI), and Scale Content Validity Index/Average (S-CVI/AVE). The initial draft comprises three domains: knowledge, awareness, and practice. Knowledge items were analyzed using IRT and demonstrated acceptable difficulty and discrimination levels. For the awareness and practice domains, EFA showed a Kaiser-Meyer-Olkin measure (KMO) of 0.83 and 0.79, respectively, with a significant Bartlett's test of Sphericity (P < 0.001). EFA yielded three factors for both awareness and practice domains with a total of 12 items for awareness and 13 items for practice, with satisfactory factor loadings (≥0.3). The final model of CFA showed good fits for both awareness and practice domains in terms of absolute, parsimonious, and comparative measures. The composite reliability of awareness was acceptable with Raykov's rho of 0.71, whereas the practice domain fell slightly below the acceptable threshold at 0.55. This was attributed to low factor loading and a limited number of items within each factor. The final questionnaire now consists of 20 items for knowledge, 10 items for awareness, and 12 items for the practice domain.