Table 3. Optimal Multivariate Linear Model for Prediction of Usual Provider Continuity Index^*

Variables	β	95% CI	P^{^†}
Clinic frequency	1.52	0.84–2.19	<.001
Patient load	−0.32	−0.45 to −0.20	<.001
Duration in practice	0.61	0.27–0.95	.001
Provider type^{^‡}	23.01	5.62–40.41	.010
Type and patient load interaction	−0.81	−1.58 to −0.04	.039
Intercept^{^§}	62.91	54.74–71.07	<.001

↵* Percentage of total clinic visits with assigned provider.
↵† P values reflect partial F-tests for significance of individual terms within the model.
↵‡ Reference group is mid-level providers (mid-level = 0, physician = 1).
↵§ Data centered around mean clinic frequency of 16.8 monthly clinic half-days (mean clinic frequency for all providers).