Psychometric properties of primary health care trust questionnaire

Trust has been introduced as the cornerstone of the public and health providers' relation. Public trust in primary health care (PHC) is crucial and must be measured. The aim of this study was to develop and validate PHC trust measurement tool.

This was a psychometric study to develop PHC trust measuring tool done in Tabriz, East-Azerbaijan with participation of 600 households in 2016. Item generation was done through literature review and experts opinions. The content validity, reliability and construct validity of the PHC trust tool were assessed using several statistical methods including modified Kappa, Kendall's Tau and intra-class correlation coefficient (ICC) as well as exploratory factor analysis (EFA). Data were analyzed using STATA 14 statistical software package.

A 30-item questionnaire was developed. The Modified Kappa coefficient as an indicator of content validity assessment was 0.94. With respect to reliability assessment, a high internal consistency was observed with 0.98 Cronbach-Alpha score and the test-retest reliability for overall scale (assessed by ICC) was 0.94 (CI: 0.87-0.97). Exploratory factor analysis emerged 2 factors. Factor 1 consisted of 25 items accounting for 74.1% of the variance (eigenvalue = 22.47) followed by Factor 2 consisting of 5 items accounting for 19.2% of the variance (eigenvalue = 1.6).

PHC trust measuring tool could be used as a valid and reliable tool by health systems in Iran and similar contexts to investigate how they are trustful from the public viewpoint.