Development of a psychometric scale to assess satisfaction with dental care among Sri Lankans.

OBJECTIVE: To develop and validate a psychometric scale to assess dental satisfaction among Sri Lankans. DESIGN: A population based cross sectional study, where the data were collected by a postal questionnaire. A 22-item scale was developed to measure dental satisfaction. PARTICIPANTS: 1,000 Sri Lankans aged 18-75 years, selected by cluster sampling with probability proportionate to size technique, using National Voters' register. OUTCOME MEASURES: Reliability of the scale was assessed by internal consistency using Cronbach's alpha and corrected item-total correlations. Construct validity was determined by factor analysis and acceptability was assessed by percentage of item-specific non-response. RESULTS: The overall response rate was 30.9%. Among respondents, analysis was limited to dental care users within two years (n=117). Item-specific non-response was low, ranging from 3.4% to 9.4%. Four (negatively worded) items were removed from the scale due to poor internal consistency (corrected item-total correlations <0.2). After removal, corrected item-total correlations of remaining 18 items were improved, ranging from 0.23 to 0.76. Factor analysis revealed a four factor solution, interpreted as: "outcome of care/clinic context" (8-items), 'factors related to treatment process" (7-items), "convenience" (2-items) and "cost of care" (single item). Identified factors explained 64.56% of the variance of the scale. The Cronbach's alpha values for the first three dimensions were 0.90, 0.87 and 0.60 respectively and for the overall construct it was 0.91. CONCLUSIONS: The present scale appeared to be a valid and reliable instrument for measuring dental satisfaction among Sri Lankans, but merits further refinements to explore detailed aspects of it.