Table 2:

Logistic regression of physician demographic characteristics associated with high-volume status^*

Characteristic	OR (95% CI)	z-score^†	p value
Female	0.14 (0.07–0.28)	−5.44	0
Full-time	1.21 (0.87–1.68)	1.14	0.2
Female^* full-time	4.62 (2.02–10.56)	3.63	0
Years in practice	1.04 (1.02–1.05)	5.42	0
Average patient age	0.99 (0.98–1.01)	−0.99	0.3
Zone 2	0.70 (0.41–1.20)	−1.31	0.2
Zone 3	0.53 (0.27–1.05)	−1.80	0.07
Zone 4	0.88 (0.52–1.50)	−0.46	0.6
Zone 5	1.95 (1.06–3.58)	2.16	0.03
Rurality	0.87 (0.79–0.95)	−2.94	0.003
International medical graduate	1.89 (1.40–2.54)	4.16	0
Constant	0.06 (0.03–0.15)	−6.23	0

Note: CI = confidence interval, OR = odds ratio.
↵* Number of observations = 3465, likelihood ratio χ² (8) = 309.94, probability > χ² = 0.000, pseudo R² = 0.19, log-likelihood = –680.46.
↵† Number of standard deviations from the mean.