Development of the outcome expectancy scale for self-care among periodontal disease patients

Rationale The theory of self-efficacy states that specific efficacy expectations affect behaviour. Two types of efficacy expectations are described within the theory. Self-efficacy expectations are the beliefs in the capacity to perform a specific behaviour. Outcome expectations are the beliefs that carrying out a specific behaviour will lead to a desired outcome. Objective To develop and examine the reliability and validity of an outcome expectancy scale for self-care (OESS) among periodontal disease patients. Methods A 34-item scale was tested on 101 patients at a dental clinic. Accuracy was improved by item analysis, and internal consistency and test-retest stability were investigated. Concurrent validity was tested by examining associations of the OESS score with the self-efficacy scale for self-care (SESS) score and plaque index score. Construct validity was examined by comparing OESS scores between periodontal patients at initial visit (group 1) and those continuing maintenance care (group 2). Results Item analysis identified 13 items for the OESS. Factor analysis extracted three factors: social-, oral- and self-evaluative outcome expectancy. Cronbach's alpha coefficient for the OESS was 0.90. A significant association was observed between test and retest scores, and between the OESS and SESS and plaque index scores. Further, group 2 had a significantly higher mean OESS score than group 1. Conclusion We developed a 13-item OESS with high reliability and validity which may be used to assess outcome expectancy for self-care. A patient's psychological condition with regard to behaviour and affective status can be accurately evaluated using the OESS with SESS.