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.

J Orthop Sports Phys Ther. 2005;35(1):24-32. doi: 10.2519/jospt.2005.1471

Key Words: instrument validation, questionnaire, self-report, survey

Study Design: Psychometric evaluation of a cross-sectional survey. Objectives: The purpose of this study was to examine the psychometric properties of reliability and validity of the Penn Shoulder Score (PSS). Background: Shoulder outcome measures are used to assess patient self-report levels of pain, satisfaction, and function. The PSS is a 100-point shoulder-specific self-report questionnaire consisting of 3 subscales of pain, satisfaction, and function. This scale has been utilized in the literature. However, the measurement properties of reliability and validity, including responsiveness, of the PSS subscales and overall scale need to be established. Methods and Measures: Patients (n = 40) with shoulder disorders undergoing a course of outpatient physical therapy completed the PSS at initial visit and again within 72 hours to assess test-retest reliability. The Constant Shoulder Score (CSS) and the American Shoulder and Elbow Surgeons Shoulder Score (ASES) were also completed at the initial visit and compared to the PSS to assess convergent construct validity. A separate cohort of patients (n = 109) completed the PSS at initial visit and 4 weeks later. These scores were used to assess internal consistency and responsiveness. Results: Reliability analysis revealed a test-retest ICC _2,1 of 0.94 (95% CI, 0.89-0.97). Internal consistency analysis revealed a Cronbach alpha of 0.93. The standard error of measurement (SEM) was ± 8.5 scale points (based on a 90% CI) and the minimal detectable change (MDC) was ± 12.1 scale points (based on a 90% CI). The minimal clinically important difference (MCID) for improvement was 11.4 points. Pearson product moment correlation coefficients between the PSS and the CSS and ASES were 0.85 and 0.87, respectively. Responsiveness analysis revealed an effect size of 1.01 and a standardized response mean of 1.27. Conclusions: This study has demonstrated that the PSS is a reliable and valid measure for reporting outcome of patients with various shoulder disorders.

J Orthop Sports Phys Ther. 2006;36(3):138-151. doi:10.2519/jospt.2006.2090

Key Words: outcome assessment, psychometrics, reliability, validity