Construction of a questionnaire based on the Health Action Process Approach for psycho-social cognitive determinants of parents in brushing children's teeth in the Netherlands

Background: The health action process approach (HAPA) model is promising to increase the frequency of brushing children's teeth by parents to improve their children's oral health. A validated HAPA questionnaire is needed as one of the measures of the effects of such an intervention.

Objectives: The aim of this study was to evaluate whether our data, based on a translated and adopted version of the Health Action Process Approach (HAPA)-based questionnaire on dental flossing, supported the constructs of the HAPA model. If so, a next aim was to assess whether these constructs could be measured reliably.

Methods: In this cross-sectional study, 269 questionnaires filled out in dental offices by parents of children 1-10 years old were analysed. Scale validation was performed according to the 6-step protocol of Dima, including Mokken scale analyses (MSA), graded response model (GRM), factor analyses and reliability measures. Pearson correlation coefficients were calculated to identify divergent validity and test-retest reliability.

Results: MSA showed a unidimensional, medium total scale. Three items were removed based on this analysis. The total scale with the remaining 26 items did not fit the GRM. Factor analysis extracted five factors and two components for the total scale. The separate subscales, except the 'intention' construct, fitted the MSA and did not fit the GRM. The data fitted a seven-factor model better than a one-factor model. Reliability measures varied from acceptable to excellent, but were poor for 'action control'. Test-retest reliability (r's 0.60-0.83) was questionable to good.

Conclusion: Our results did not fully support the constructs of the HAPA model. To support the HAPA constructs, modification to the subscales risk perceptions, intention, action planning, action control and self-reported behaviour are suggested. With these adjustments, the reliability and validity of the questionnaire could be significantly improved"