Between-practice variation in the unadjusted and adjusted mixed model by type of investigation
| Model | Any investigation SD (95% CI) | Blood test SD (95% CI) | Imaging SD (95% CI) |
| Model 1* (unadjusted) | 0.36 (0.33 to 0.38) | 0.37 (0.35 to 0.40) | 0.29 (0.26 to 0.33) |
| Model 3* (adjusted for patient factors) | 0.44 (0.41 to 0.47) | 0.47 (0.44 to 0.51) | 0.32 (0.29 to 0.36) |
| Model 4 (adjusted for patients and practice factors) | 0.44 (0.41 to 0.48) | 0.47 (0.43 to 0.50) | 0.32 (0.29 to 0.36) |
*P<0.001 for all models.