Nonparametric Subgroup Identification by PRIM and CART: A Simulation and Application Study

Table 2

Proportions of cases with a predicted subgroup when using the methods PRIM () and CART (pruned) for given observations and one or two true subgroups. Results for the methods PRIM (opt. ) and CART (maxdepth) are not shown here, because their proportions were 1 for each and .

	Method	0	0.33	0.67	1	1.33	1.67	2	2.33	2.67	3
5%	PRIM ()	0.05	0.07	0.14	0.32	0.55	0.76	0.9	0.98	1	1
	CART (pruned)	0.03	0.04	0.04	0.05	0.18	0.18	0.2	0.27	0.37	0.47
5% (margin)	PRIM ()	0.08	0.08	0.09	0.21	0.4	0.69	0.86	0.93	0.98	0.99
	CART (pruned)	0.08	0.06	0.08	0.13	0.41	0.58	0.69	0.77	0.86	0.92
20%	PRIM ()	0.1	0.2	0.58	0.9	0.99	1	1	1	1	1
	CART (pruned)	0.04	0.06	0.15	0.41	0.85	0.97	1	1	1	1
40%	PRIM ()	0.11	0.34	0.82	1	1	1	1	1	1	1
	CART (pruned)	0.08	0.1	0.35	0.91	1	1	1	1	1	1
2 × 5%	PRIM ()	0.08	0.08	0.14	0.36	0.63	0.86	0.97	1	1	1
	CART(pruned)	0.17	0.19	0.06	0.08	0.11	0.16	0.24	0.31	0.4	0.54
2 × 5% (margin)	PRIM ()	0.05	0.07	0.11	0.25	0.5	0.82	0.97	1	1	1
	CART (pruned)	0.2	0.21	0.08	0.13	0.3	0.61	0.8	0.9	0.95	0.97
2 × 10%	PRIM ()	0.06	0.15	0.34	0.71	0.93	1	1	1	1	1
	CART (pruned)	0.14	0.13	0.03	0.08	0.25	0.56	0.76	0.86	0.92	0.96
2 × 20%	PRIM ()	0.08	0.24	0.67	0.97	1	1	1	1	1	1
	CART (pruned)	0.16	0.17	0.08	0.18	0.42	0.69	0.81	0.89	0.92	0.96