Decisional Balance Inventory (DBI) Adolescent Form for Smoking: Psychometric Properties of the Persian Version

One effective model for studying cigarette smoking cessation is the transtheoretical model (TTM). In order to assess to what degree interventions can make variations in individuals' behavior, several questionnaires have been developed based on the TTM. This study aims to describe the development of the Persian version of the Decisional Balance Inventory (DBI) for smoking cessation in Iran and to evaluate its psychometric properties.

The forward-backward technique was used to translate the DBI from English into Persian. After linguistic validation and a pilot test among 30 male smoking young adults, a cross-sectional study was performed, and psychometric properties of the Persian version of the DBI were assessed. Using a convenience sampling method, 120 male smokers between 16 and 24 years of age were recruited from three factories in Nowshahr, Iran. In order to assess the reliability of the DBI, internal consistency and test-retest methods were performed. Additionally, face and content validity were assessed, and the construct validity of the DBI was calculated by performing both exploratory and confirmatory factor analysis. Data were analyzed using SPSS and AMOS.

The mean age of the sample (n = 120) was 20.19 (SD = 2.13) years. The mean scores for the content validity index (CVI) and the content validity ratio (CVR) were .94 and .89, respectively. The results of exploratory factor analysis (EFA) showed a three-factor solution for the DBI that accounted for 55.4% of observed variance. The results achieved from the confirmatory factor analysis (CFA) displayed that the data fit the model: the relative chi-square (×2/df) = 1.733 (p < .001) and the root mean square error of approximation (RMSEA) = .07 (90% CI = .05-.105). All comparative indices of the model including GFI, AGFI, CFI, NNFI, and NFI were more than .80 (.87, .83, .91, .89, and .81, respectively). The Cronbach's alpha ranged from .78 to .83, indicating an acceptable reliability. Furthermore, the intraclass correlation coefficient (ICC) ranged from .72 to .89, confirming a satisfactory result.

The results from the present study indicate that the Persian version of the DBI has good psychometric properties and is suitable to measure smoking behaviors among Iranian adolescent and young adult smokers. Consequently, the instrument could be used in planning cigarette smoking cessation interventions among Iranian adolescents and young adults.