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

Abstract

ABSTRACTObjectivesIn this study it was 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 dialogue tool (MPH). 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.ParticipantsResponse rate was 76%, 1327 of a total of 2457 respondents were female, and mean age (year) was 53.3 ± 17.8.MethodsFirst, item reduction was carried out through content discussions following statistical output retrieved from factor structures and loadings, inter-item correlations (IIC) and internal consistency (Cronbach’s alphas). 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 analyses (CFA).ResultsThe 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 alphas were 0.84, 0.92, 0.81, and 0.78 for the renamed factors ‘Physical fitness’ (5 items), ‘Contentment with life’ (9 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– and second-order CFA. The scores of the PH22 were normally distributed. No floor or ceiling effects were present.ConclusionsA 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-centered 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 be known also. Future research has to reveal this.Strengths and limitations of this studyThe main strength of this study was that the choice to keep or remove an item during the development of the short Positive Health questionnaire was not only based on statistical output such as factor loadings, but combined with thorough content discussion by the expert team and judgement of inter-item correlations and internal consistency.This study is robust in terms of its large sample size, the high response rate and the representativeness of the general Dutch population.Development of the short Positive Health questionnaire was based on the items of the My Positive Health dialogue tool, which is widely used in the Netherlands.It can be argued that content discussion is less objective or transparent to follow than statistical output. To overcome this, the results from the content discussion were thematized and each step of the item reduction process thoroughly reported.Choices made by the expert team, might have been more support-based if more representatives were included in the content discussion, i.e., if focus groups were organized. Nevertheless, the members of the research team represent different backgrounds and relevant expertise. Moreover, it should be realized that the basic set of items of the My Positive Health dialogue tool was based on health indicators retrieved from a large study among various stakeholders and judged relevant.