Table 3.

Comparing distributed Cox regression, pooled Cox regression, and meta-analyses with simulated data from unstratified models with a varying number of sites , site sizes and number of covariates . True log HR for treatment is . Number of replications 10000.

	Unstratified pooled	Unstratified distributed	Stratified pooled	Stratified distributed	Multivariate meta-analysis	Univariate meta-analysis
	; ; ;
bias	0.1536	0.0194	0.2000	0.0428	0.2276	0.2276
cr	0.9591	0.9749	0.9577	0.9869	0.9595	0.9595
mae	0.3297	0.3123	0.3567	0.3161	0.3648	0.3648
cios	0.9500	0.9041	0.9272	0.8961	0.9234	0.9234
sse	0.3843	0.3910	0.4037	0.3903	0.3944	0.3944
ese	0.4526	0.5556	0.4969	0.6304	0.5022	0.5022
rse	0.4314	0.5575
	; ; ;
bias	0.0065	0.0615	0.0108	0.0579	0.0250	0.0250
cr	0.9614	0.9630	0.9609	0.9696	0.9609	0.9609
mae	0.1931	0.2049	0.2009	0.2122	0.2001	0.2001
cios	0.9500	0.9305	0.9399	0.9227	0.9389	0.9389
sse	0.2427	0.2482	0.2523	0.2577	0.2504	0.2504
ese	0.2551	0.2770	0.2658	0.2956	0.2661	0.2661
rse	0.2496	0.2780
	; ; ;
bias	0.0052	0.0457	0.0069	0.0442	0.0128	-0.0100
cr	0.9572	0.9606	0.9565	0.9635	0.9583	0.9555
mae	0.1706	0.1779	0.1785	0.1853	0.1769	0.1801
cios	0.9500	0.9334	0.9389	0.9249	0.9388	0.9360
sse	0.2134	0.2176	0.2231	0.2273	0.2210	0.2250
ese	0.2175	0.2337	0.2274	0.2479	0.2270	0.2300
rse	0.2122	0.2394
	; ; ;
bias	0.0826	0.0089	0.1023	0.0342	0.1058	0.1191
cr	0.9517	0.9750	0.9544	0.9830	0.9577	0.9491
mae	0.2408	0.2381	0.2583	0.2482	0.2539	0.2769
cios	0.9500	0.9146	0.9310	0.9050	0.9306	0.9166
sse	0.2921	0.2991	0.3099	0.3114	0.3025	0.3299
ese	0.3035	0.3657	0.3260	0.4050	0.3268	0.3463
rse	0.2892	0.3833
	; ; ;
bias	0.0008	0.0489	0.0018	0.0542	0.0060	0.0014
cr	0.9573	0.9697	0.9532	0.9739	0.9554	0.9505
mae	0.0794	0.0925	0.0830	0.0997	0.0821	0.0871
cios	0.9500	0.9057	0.9379	0.8794	0.9376	0.9289
sse	0.0991	0.1044	0.1038	0.1117	0.1025	0.1088
ese	0.0992	0.1150	0.1042	0.1440	0.1040	0.1074
rse	0.0983	0.1238
	; ; ;
bias	0.0022	0.0130	0.0027	0.0136	0.0022	0.0048
cr	0.9500	0.9569	0.9489	0.9510	0.9490	0.9443
mae	0.0778	0.0801	0.0789	0.0813	0.0787	0.0808
cios	0.9500	0.9427	0.9470	0.9407	0.9470	0.9432
sse	0.0976	0.0997	0.0989	0.1012	0.0987	0.1014
ese	0.0968	0.1003	0.0980	0.1019	0.0979	0.0993
rse	0.0957	0.1037
	; ; ;
bias	0.0006	0.0178	0.0007	0.0190	0.0016	0.0021
cr	0.9505	0.9730	0.9505	0.9723	0.9518	0.9416
mae	0.0785	0.0824	0.0803	0.0850	0.0798	0.0858
cios	0.9500	0.9285	0.9446	0.9123	0.9442	0.9337
sse	0.0983	0.1016	0.1003	0.1047	0.0996	0.1074
ese	0.0976	0.1092	0.0998	0.1281	0.0997	0.1041
rse	0.0961	0.1176

cr: coverage rate; mse: mean absolute error; cios: confidence interval overlap statistics

sse: sample standard error; ese: estimated standard error; rse: robust standard error estimate.