Abstract
Objective: We developed the Decisional Balance Scale of vegetable consumption behavior, and examined the validity and the reliability of the scale.
Methods: In September 2009, a self-administered questionnaire was completed by Japanese male employees aged 20-59 years, working at 20 worksites of Niigata City in Japan. The scale about decisional balance of vegetable consumption behavior was composed of 6 items selected from an existing scale: 3 items assessing the potential benefits (pros) and 3 items assessing the potential costs (cons). The internal consistency of the scale was examined using Cronbach's alpha, construct validity was examined using confirmatory factor analysis, and criterion-related validity was determined by assessing the association between the scale scores and the stages of change.
Results: Of 600 respondents, the data of 527 participants (mean age, 41.1 years) were analyzed. By using item analysis, the newly developed scale was reduced to 4 items, 2 pros and 2 cons. Results indicated that the scale had sufficient reliability (Cronbach's alpha: pros = 0.76, cons = 0.74). Moreover, the scale provided the best data fit (χ2 = 0.024, p = 0.878, GFI = 1.000, AGFI = 1.000, RMSEA = 0.000). The score for pros was higher in the preparation than in the precontemplation stage (p < 0.05). Conversely, the score for cons was lower in the preparation and action/maintenance than in the precontemplation stage (p < 0.05). Furthermore, it was lower in the action/maintenance than in the contemplation stage (p < 0.05).
Conclusion: The Decisional Balance Scale has sufficient validity and reliability for male workers, as demonstrated by the internal consistency of the scale, as well as by its construct and criterion-related validity.
