A Psychometric Validation of the Beliefs Toward Mental Illness Scale

Background and Purpose: This study measured Protestant Christians' beliefs about mental illness using the Beliefs Toward Mental Illness Scale (BMI). Methods: This study used a state-of-the-art item response theory technique, namely the Rasch rating scale model (RRSM), to evaluate the psychometric properties of the BMI and to produce a ruler of the construct hierarchy. Results: Using Messick's framework for evaluating construct validity, sufficient evidence was obtained that suggests the BMI is psychometrically sound regarding substantive, content, structural, and generalizable aspects of validity. Conclusions: The BMI is a psychometrically sound instrument that is appropriate for measuring beliefs toward mental illness.