Modern medical practice emphasises mutual decision-making between healthcare professionals and patients. This pre-requisites health self-efficacy and health assertiveness in patients. However, lack of general health self-efficacy and health assertiveness measure limits research in the local setting. This study aimed to translate and validate Health Efficacy and Assertiveness Scale (HEAS) into Malay language. Malay version of HEAS was obtained through back-to-back translation process. This was tested for factorial validity via exploratory (EFA) and confirmatory factor analysis (CFA) using structural equation modelling. Reliability was established using Cronbach’s alpha. Five items measured health self-efficacy whereas eight items measured health assertiveness on two subdimensions (assert to be informed and assert opinion). Reliability index was 0.76 for health self-efficacy and 0.73 for health assertiveness. CFA on health efficacy measurement model reporting fit indices: χ2/df 1.28, comparative fit index (CFI) 0.96, Tucker-Lewis’s index (TLI) 0.94, and root mean-square error of approximation (RMSEA) was 0.07. CFA on health assertiveness revealed improved fit indices: χ2/df was 1.52, comparative fit index (CFI) 0.94, Tucker-Lewis’s index (TLI) 0.91, and root mean-square error of approximation (RMSEA) was 0.10. Thus, the Malay HEAS questionnaire established acceptable factorial validity and good reliability on Cronbach’s alpha. Universal nature of the items allowed use in different population and health scenarios.

Quantitative study on risk perception in vaccination encompasses various theoretical basis, health context, and psychometric validity and reliability. In the context of basic childhood vaccination, there was a lack of locally validated and reliable instrument to measure risk perception for vaccine-preventable disease. As such, this study aimed to validate and assess reliability of developed instruments in Malay language. Items were generated from available items in previous research and adopting recommendations on operationalising the construct. Generated items were measured for content validity index by seven experts, tested for factorial validity using exploratory (EFA) and confirmatory factor analysis (CFA) using structural equation modelling. Reliability was established using Cronbach’s alpha. Seven items measured perceived likelihood whereas eight items measured perceived severity. Reliability index was 0.97 for perceived likelihood and 0.94 for perceived severity. CFA on second-order measurement model revealed satisfactory model fit χ2/df (1.55), CFI 0.96, TLI 0.95, and RMSEA 0.11. The average variance explained was 0.73 for perceived likelihood and 0.73 for perceived severity and CR was 0.95 and 0.96 for perceived likelihood and perceived severity, respectively. Both constructs showed significant positive correlation (r = 0.19, p < 0.01) with each other indicating divergent validity. Thus, the Malay risk perception questionnaire established good content, factorial, and divergent validity, as well as good reliability on Cronbach’s alpha. The instrument should be valuable to re-examine risk perception’s role in the resurgence of vaccine hesitancy in the local population.