Study design: Psychometric evaluation of a cross-sectional survey.
Objectives: To determine the validity of measures obtained from the MedRisk Instrument for Measuring Patient Satisfaction With Physical Therapy Care (MRPS) to differentiate between patient satisfaction with internal and external factors.
Background: Self-report measures that sample a variety of items provide clinicians with an array of information that may assist in assessing patient satisfaction. An important measurement characteristic of these instruments is the ability to discriminate between different factors that may influence patient reports of satisfaction with care, ie, discriminant validity. In previous work, exploratory factor analysis suggested that the MRPS questionnaire has a 2-factor structure: "internal," relating to the patient-therapist interaction, and "external," describing nontherapist issues such as admissions and clinic environment.
Methods and measures: One thousand four hundred forty-nine adult patients completed the MRPS questionnaire upon finishing their course of outpatient physical therapy treatment. Discriminant validity of the 2-factor model was assessed using confirmatory factor analysis. The measures from the 2 factors were then evaluated for reliability by calculating the standard error of measurement (SEM), and for concurrent validity by correlating the mean score of the factors and individual items to global measures of satisfaction.
Results: Confirmatory factor analysis supported a good to excellent model fit for the internal factor (7 items) and external factor (3 items). The SEM for the 2 factors was 0.19 and 0.24, indicating a low degree of measurement error. Both factors had high significant correlation with global measures of satisfaction (internal, r = 0.83 and 0.80; external, r = 0.71 and 0.71). All individual items within the 2 factors had significant correlations with global measures ranging from r = 0.33 to 0.80.
Conclusions: Our findings provide evidence of discriminant and concurrent validity of the 2-factor solution for the MRPS questionnaire for the sample that was tested. This 2-factor solution yields measures that are relatively free of error and may discriminate between internal and external factors influencing patient satisfaction. Patients who complete their course of physical therapy report that the professional interaction between the therapist and patient, especially the meaningful exchange of relevant information, is critical for patient satisfaction with care. The generalizability of our data to patients who do not complete their physical therapy care or who are receiving care in other health care environments is unknown.