Objectives A core construct of the Transtheoretical model is that the processes and stages of change are strongly related to observable behavioral changes. We created the Processes of Change Scale of vegetable consumption behavior and examined the validity and reliability of this scale.
Methods In September 2009, a self-administered questionnaire was administered to male Japanese employees, aged 20–59 years, working at 20 worksites in Niigata City in Japan. The stages of change (precontempration, contemplation, preparation, action, and maintenance stage) were measured using 2 items that assessed participants’ current implementation of the target behavior (eating 5 or more servings of vegetables per day) and their readiness to change their habits. The Processes of Change Scale of vegetable consumption behavior comprised 10 items assessing 5 cognitive processes (consciousness raising, emotional arousal, environmental reevaluation, self-reevaluation, and social liberation) and 5 behavioral processes (commitment, rewards, helping relationships, countering, and environment control). Each item was selected from an existing scale. Decisional balance (pros [2 items] and cons [2 items]), and self-efficacy (3 items) were also assessed, because these constructs were considered to be relevant to the processes of change. The internal consistency reliability of the scale was examined using Cronbach's alpha. Its construct validity was examined using a factor analysis of the processes of change, decisional balance, and self-efficacy variables, while its criterion-related validity was determined by assessing the association between the scale scores and the stages of change.
Results The data of 527 (out of 600) participants (mean age, 41.1 years) were analyzed. Results indicated that the Processes of Change Scale had sufficient internal consistency reliability (Cronbach's alpha: cognitive processes=0.722, behavioral processes=0.803). The processes of change were divided into 2 factors: “consciousness raising, emotional arousal, environmental reevaluation, self-reevaluation, commitment, rewards, helping relationships, and social liberation” and “countering and environment control” in the factor analysis. Moreover, each construct — the processes of change, decisional balance, and self-efficacy — could be classified into different factors. The scores for cognitive processes were higher in the contemplation and preparation stages than in the precontemplation stage (P<0.05). Scores for behavioral processes increased from the precontemplation stage to the preparation stages (P<0.05), and were higher in the action+maintenance stage than in the precontemplation stage (P<0.05).
Conclusion For male workers, the Processes of Change Scale has sufficient validity and reliability, as demonstrated by the internal fitness and the construct and criterion-related validity of the scale found in this study.

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