Table 4.

The estimated one-year and three-year restricted mean treatment effect (in days) with 95% confidence intervals (in parenthesis) and the stacking weights by center volume [ie., ${\widehat{\alpha }}_k^{(a)}$] for each survival model in the lung transplant example. The stacked model includes random survival forests (RSF).

	Model	Restricted Mean Treatment Effect with 95% CI	Estimated Model Weights
			Low Volume Centers	High Volume Centers
One Year	Cox	5.0 (-0.4, 10.4)	0.000	0.339
	Cox with Splines	6.0 (0.6, 11.3)	0.225	0.275
	log-Normal	8.0 (2.4, 13.6)	0.243	0.000
	Weibull	6.5 (1.2, 11.8)	0.000	0.000
	RSF	5.5 (-14.1, 25.0)	0.532	0.386
	Stacked	7.3 (-4.0, 18.7)	n/a	n/a
Three Year	Cox	21.3 (-3.4, 46.0)	0.000	0.339
	Cox with Splines	27.1 (2.2, 52.1)	0.225	0.275
	log-Normal	24.8 (1.2, 48.4)	0.243	0.000
	Weibull	23.9 (-0.3, 48.0)	0.000	0.000
	RSF	26.1 (-51.2, 102.1)	0.532	0.386
	Stacked	25.8 (-17.4, 68.3)	n/a	n/a