Development and cross-validation of a short questionnaire to evaluate self-reported positive health: a cross-sectional panel study of structural validity among a general Dutch population

Objectives This study aimed to further develop and cross-validate a short questionnaire to measure self-reported Positive Health in general (Dutch) populations for evaluative purposes, stemming from the original 42 items of the My Positive Health (MPH) dialogue tool. Positive Health refers to 'health from the perspective of patients and citizens' following the concept of Huber et al.Design and setting A cross-sectional study was performed among a panel representative for the general adult Dutch population living at home.Participants The response rate was 76%, 1327 of a total of 2457 respondents were female, and mean age (years) was 53.3 +/- 17.8.Methods First, item reduction was carried out through content discussions following statistical output retrieved from factor structures and loadings, inter-item correlations and internal consistency (Cronbach's alpha). Next, among the other half of the study population, measurement properties for the developed short questionnaire were calculated using goodness of fit indices from confirmatory factor analysis (CFA).Results The item reduction process (n=1199) resulted in a questionnaire of 22 items (PH22) with a four-factor structure and explained variance of 62.4%. Cronbach's alpha values were 0.84, 0.92, 0.81 and 0.78 for the renamed factors 'Physical fitness' (5 items), 'Contentment with self, others and life' (nine items), 'Daily life management' (5 items) and 'Future perspective' (3 items), respectively. Cross-validation (n=1258) showed adequate goodness-of-fit indices of the PH22, based on both first-order and second-order CFA. The scores of the PH22 were normally distributed. No floor or ceiling effects were present.Conclusions A short 22-item questionnaire to measure self-reported Positive Health in a general (Dutch) population for evaluative purposes such as scientific or policy research at Positive Health or patient-centred interventions was developed and cross-validated, named PH22. This study supports its structural validity. To use this questionnaire in practice, its test-retest reliability and responsiveness should also be known. Future research has to reveal this.