Developing a Motivation –To–Quit Scale among Thai Adolescent Smokers

Abstract

Motivation has been consistently a powerful predictor of smoking cessation among adolescents. Health care professionals need to assess adolescents’ motivation to quit. However, there is currently no valid and reliable measure to assess this. The purpose of this study was to develop motivation to quit scale (MTQS) for Thai adolescent smokers. This study was guided by the scale development procedures, which consist of two phases: I) scale construction and II) psychometric testing. Different sample groups were used in the phases. Firstly, the items generated were drawn from a comprehensive literature review, self-determination theory, and existing measures. The content validity of the first draft was established by seven experts. Results of item-analysis and item-review from a convenience sample of 230 adolescent smokers in Bangkok were used for constructing the second draft of the scale. Finally, 319 adolescent smokers in Bangkok were selected to validate the structure of the final scale by confirmatory factor analysis. The MTQS is a self-reported questionnaire that consists of 36 items with 5-Likert scale. It contains two dimensions: intrinsic and extrinsic motivation. Psychometric testing demonstrated satisfactory internal consistency and validity of the instrument for Thai adolescent smokers with α coefficient of 0.96. Construct validity was supported by confirmatory factor analysis. In conclusion, the MTQS is a reliable and valid instrument. The scale could be used as a tool for determining adolescent smokers’ motivation to engage in smoking cessation behavior.