Psychometric properties of a Protection Motivation Theory based questionnaire for tobacco use in male adolescents

The aim of the present study was to design and validate a protection motivation theory based questionnaire in relation with tobacco use among young population of Iran.
The items of the questionnaire were first formulated through the use of qualitative content analysis guided by the male high school students. Then the psychometric features of the questionnaire were tested with the use of face validity, content validity, construct validity, internal consistency and stability.
The primary questionnaire was formed including 64 items. After content validity three items were omitted. Also 6 items were removed after face validity and overall the questionnaire was reduced to 55 items. The results of factor analysis showed the existence of nine factors for protection motivation theory including perceived vulnerability, perceived severity, fear, perceived self-efficacy, response cost, efficiency of the perceived response, perceived extrinsic reward, perceived intrinsic reward and protection motivation. These nine factors totally explained 60.17 % of the variance. The results of the confirmatory factor analysis also confirmed the factors of protection motivation theory. The values of Cronbach’s alpha for the constructs of the questionnaire varied from 0.77-0.95 to 0.85-0.93.
The designed questionnaire had good validity and can be used for measuring the predictors of tobacco use among the youth population of Iran.