Further validation and reliability testing of the Trust in Physician Scale. The Stanford Trust Study Physicians.

OBJECTIVES: To further validate and assess the reliability and validity of the Trust in Physician Scale.

METHODS: Consecutive adult patients (n = 414) from 20 community-based, primary care practices were enrolled in a prospective, 6-month study. At enrollment, subjects completed the 11-item Trust in Physician Scale plus measures of demographics, preferences for care, and satisfaction with care received from the physician. Continuity, satisfaction with care, and self-reported adherence to treatment were measured at 6 months. Reliability, construct validity, and predictive validity were assessed using correlation coefficients and analysis of variance techniques.

RESULTS: The Trust in Physician Scale showed high internal consistency (Cronbach's alpha = .89) and good 1-month test-retest reliability (intraclass correlation coefficient = .77). As expected, trust increased with the length of the relationship and was higher among patients who actively chose their physician, who preferred more physician involvement, and who expected their physician to care for a larger proportion of their problems (P < 0.001 for all associations). Baseline trust predicted continuity with the physician, self-reported adherence to medication, and satisfaction at 6 months after adjustment for gender, age, education, length of the relationship, active choice of the physician, and preferences for care. After additional adjustment for baseline satisfaction with physician care, trust remained a significant predictor of continuity, adherence, and satisfaction.

CONCLUSIONS: The Trust in Physician Scale has desirable psychometric characteristics and demonstrates construct and predictive validity. It appears to be related to, but still distinct from, patient satisfaction with the physician and, thus, provides a valuable additional measure for assessment of the quality of the patient-physician relationship.