The Norwegian patient experiences with GP questionnaire (PEQ-GP): reliability and construct validity following a national survey

OBJECTIVES: The aim of this study was to test the reliability and validity of a new questionnaire for measuring patient experiences with general practitioners (PEQ-GP) following a national survey. SETTING: Postal survey among patients on any of 500 GPs patient lists in Norway. GPs were stratified by practice size and geographical criteria. PARTICIPANTS: 4964 patients who had at least one consultation with their regular GP in the foregoing 12 months were included in the study. The patients were randomly selected after the selection of GPs. 2377 patients (49%) responded to the survey. PRIMARY AND SECONDARY OUTCOME MEASURES: The items were assessed for missing data and ceiling effects. Factor structure was assessed using exploratory factor analyses. Reliability was tested with item–total correlation, Cronbach’s alpha and test–retest correlations. Item discriminant validity was tested by correlating items with all scales. Construct validity was assessed through associations of scale scores with health status, the patients’ general satisfaction with the services, whether the patient had been incorrectly treated by the GP and whether the patient would recommend the GP to others. RESULTS: Item missing varied from 1.0% to 3.1%, while ceiling effects varied from 16.1% to 45.9%. The factor analyses identified three factors. Reliability statistics for scales based on these three factors, and two theoretically derived scales, showed item–total correlations ranging from 0.63 to 0.85 and Cronbach’s alpha values from 0.77 to 0.93. Test–retest correlation for the five scales varied from 0.72 to 0.88. All scales had the expected association with other variables. CONCLUSIONS: The PEQ-GP has good evidence for data quality, internal consistency and construct validity. The PEQ-GP is recommended for use in local, regional and national surveys in Norway, but further studies are needed to assess the instrument’s ability to detect differences over time and between different GPs.