Table 3.
Sample Size Requirements to Achieve Desired Reliabilities of Physician-Level Performance on Patient Experience Measures Under Varying Levels of Adjustment for Patient Characteristics
| Extent of adjustment for patient characteristics | Patient-level ICC (95% CI), % | Physician level ICC (95% CI), % | Sample size to achieve α = 0.70 (95% CI) | Sample size to achieve α = 0.80 (95% CI) | Sample size to achieve α = 0.90 (95% CI) |
|---|---|---|---|---|---|
| No adjustment | 45.0 (35.0, 55.0) |
6.4 (2.6, 10.2) |
34 (21, 88) |
59 (35, 150) |
132 (79, 338) |
| Standard adjustment* | 41.6 (31.2, 52.0) |
6.1 (2.4, 9.8) |
36 (22, 94) |
62 (37, 161) |
138 (83, 362) |
| Expanded adjustment* | 33.8 (21.1, 46.5) |
3.4 (0.7, 6.2) |
66 (36, 351) |
113 (61, 602) |
255 (137, 1355) |
ICC intraclass correlation coefficient
*Standard adjustment includes covariates recommended for case-mix adjustment by the Consumer Assessment of Healthcare Providers and Systems (CAHPS) program, while expanded adjustment includes additional patient-level covariates