Adaptation, Translation and Psychometric Evaluation of the Thai Version of the Beliefs about Medicines Questionnaire for Chemotherapy among Breast Cancer Patients
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Abstract
This study aimed to adapt, translate, and evaluate the psychometric properties of the Beliefs about Chemotherapy Questionnaire for Thai breast cancer patients, consisting of 11 items. The translation process followed the forward–backward translation method based on Brislin’s guidelines (1970). The study was conducted in two phases. Phase 1 involved adaptation, translation, and content validity assessment. A professional bilingual translator conducted the translation, and the back-translated version was reviewed by the original instrument developer. The Thai version was evaluated by five experts and revised according to their recommendations to ensure semantic equivalence with the original instrument. Phase 2 examined the reliability of the instrument in a sample of 30 breast cancer patients aged 18 years and older who were deciding whether to undergo chemotherapy at a tertiary hospital. Data were analyzed using Cronbach’s alpha coefficient.The results indicated that the Thai version had excellent content validity, with an Item‑Content Validity Index (I‑CVI) and Scale‑Content Validity Index/Average (S‑CVI/Ave) of 1, demonstrating that the items were comprehensive, appropriate, and consistent with the purpose of measuring beliefs about chemotherapy. The reliability test showed a high internal consistency with a Cronbach’s alpha coefficient of 0.947. In conclusion, the Thai version of the questionnaire demonstrated both good content validity and reliability, making it suitable for assessing beliefs about chemotherapy among breast cancer patients.
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