Behavioral Intention Scale for End-of-life DiscussionsReliability and Validity Using a Web-based Survey

ABSTRACT

Purpose: The purpose of this study was to examine the reliability and validity of the behavioral intention scale for end-of-life discussions. Methods: The scale items were developed according to the Theory of Planned Behavior. The drafts of the scale were created by Item-Level Content Validity Index (I-CVI) and a preliminary test. In the main study, we administered a cross-sectional questionnaire on the web to the participants 20–79 years of age (n=860), living in Tokyo and six surrounding prefectures, and a retest one week later (n=665). We examined item analysis, calculation of a reliability coefficient (intraclass correlation coefficient, Cronbach's alpha coefficient), construct validity, and concurrent validity of the scale. Results: Six factors identified by an exploratory factor analysis were; outcome evaluation, perceived power, control beliefs, motivation to comply, normative beliefs, and behavioral beliefs. The alpha coefficient of the overall scale was .96. The effect size that was determined based on known-groups validity and the correlation coefficient determined on the basis of concurrent validity were moderate. Conclusions: The reliability and validity of the scale were generally confirmed.