Development and validation of a questionnaire assessing knowledge, attitude, perception, safety practices, and health effects related to occupational hazards among e-waste workers in Malaysia

Introduction The growing amount of electronic waste (e-waste) creates serious occupational safety and health risks worldwide. This study aimed to develop and psychometrically validate the E-Waste Integrated Safety and Health Effects (E-WISE) questionnaire to evaluate knowledge, attitudes, perceptions, safety practices, and health effects among formal e-waste recovery workers in Malaysia. Methodology The E-WISE domains were identified through a literature review and expert verification. The questionnaire was developed in Malay using a multistage questionnaire development framework. Content validation by six experts ensured relevance and accuracy, while face validation with ten e-waste workers assessed clarity. A pretest evaluated the questionnaire’s practicality. Item analysis for the Knowledge domain examined difficulty and discrimination indices. Exploratory Factor Analysis using Principal Axis Factoring and internal consistency reliability analyses were performed to evaluate the questionnaire’s construct structure and internal stability. Results A total of 76 e-waste workers from 18 licensed recovery facilities across eight Malaysian states participated. Content and face validation showed excellent relevance and clarity (S-CVI/Ave = 0.99–1.00; S-FVI/Ave = 0.97–1.00). Item analysis for the Knowledge domain indicated acceptable difficulty ( p = 0.50–0.88) and strong discrimination (DI = 0.43–0.90). EFA confirmed a one-factor structure for the Attitude and Perception domains and a two-factor structure for Safety Practices representing personal protective equipment and hygiene compliance and adherence to safety procedures, accounting for 56.11% of the total variance. All domains demonstrated satisfactory to excellent reliability (KR-20/Cronbach’s α = 0.82–0.97), supporting the internal stability of the E-WISE questionnaire. Conclusion The E-WISE questionnaire demonstrated strong validity and reliability in assessing occupational safety and health among e-waste recovery workers. The instrument provides a structured and context-specific tool for evaluating occupational safety culture, safety practices, and health effects within formal e-waste recovery facilities in Malaysia and may support future occupational health monitoring and intervention efforts.