Aims of the study: To describe three stages in the development of an instrument to measure service quality from the patients' perspective in hospital outpatient departments.
Rationale: A reliable and valid service quality instrument is a valuable tool for collecting feedback from patients when improving outpatient services.
Design: A multiphase process with several versions of the questionnaire testing its validity and reliability. The first version of the questionnaire was constructed from information collected in a previous interview study of patients' service experiences. Using this version (47 questions) information was collected in 15 outpatient departments (314 patients) and the second version of the questionnaire was developed. At this stage, a survey of employees (n=111) was included in the development process. This second version of the questionnaire (43 questions) was used to collect more data in three outpatient departments of a university hospital and in two outpatient departments of two regional hospitals on three different occasions (1416, 369 and 124 patients) within a period of 2 years. The reliability of the instrument was tested in terms of stability by using three repeated measurements, and using the Cronbach's alpha coefficient as an indicator of internal consistency. Content validity was assessed by means of percentage agreement between staff and patients. Logistic regression analysis was performed to assess construct validity.
Results: The final version of the questionnaire contained 12 items. Agreement between patient and staff ratings was found to be acceptable for most questions (content validity). Two measurements on different occasions yielded a similar structure (construct validity). Internal consistency was acceptable (Cronbach's alpha = 0.67-0.93 in the first and 0.71-0.94 in the second survey). The variance of the alpha coefficients was small in the retest (stability).
Conclusions: The instrument developed is general to the extent that it is suitable for assessing service quality improvement needs in individual units and for making cross-departmental comparisons.