Table 1.

Comparing distributed Cox regression (Dist), pooled Cox regression (pooled), multivariate meta-analysis (MultiV) and univariate meta-analysis (UniV) with simulated data of sample sizes under unstratified and stratified models. Sizes for the data-contributing sites are approximately the same and provided in the table below. Covariates distributions for all the data-contributing sites are the same. True log HR value is . Number of replications 10 000

	Data generating model: unstratified								Data generating model: stratified
Method	Unstratified		Stratified		Meta-analysis				Unstratified		Stratified		Meta-analysis
	Pooled	Dist	Pooled	Dist	MulV	UniV			Pooled	Dist	Pooled	Dist	MulV	UniV
	; ;								; ;
bias	0.0035	0.0146	0.0033	0.0145	0.0026	0.0047		bias	0.0316	0.0168	0.0033	0.0143	0.0026	0.0046
cr	0.9542	0.9556	0.9523	0.9530	0.9525	0.9501		cr	0.9404	0.9711	0.9536	0.9519	0.9544	0.9518
mae	0.0785	0.0805	0.0796	0.0816	0.0794	0.0803		mae	0.0834	0.0818	0.0791	0.0811	0.0789	0.0799
cios	0.9500	0.9455	0.9470	0.9429	0.9470	0.9453		cios	0.9053	0.9141	0.9500	0.9462	0.9500	0.9483
sse	0.0985	0.0999	0.0999	0.1015	0.0997	0.1009		sse	0.0994	0.1011	0.0993	0.1008	0.0991	0.1004
ese	0.0992	0.1012	0.1005	0.1026	0.1004	0.1011		ese	0.0987	0.1031	0.1003	0.1023	0.1001	0.1009
rse	0.0984	0.1025						rse	0.0993	0.1161
	; ;								; ;
bias	0.0011	0.0066	0.0011	0.0065	0.0008	0.0018		bias	0.0344	0.0255	0.0009	0.0064	0.0006	0.0016
cr	0.9494	0.9498	0.9485	0.9505	0.9488	0.9483		cr	0.9189	0.9604	0.9469	0.9483	0.9470	0.9467
mae	0.0557	0.0565	0.0561	0.0568	0.0561	0.0565		mae	0.0628	0.0604	0.0562	0.0568	0.0562	0.0565
cios	0.9500	0.9480	0.9484	0.9466	0.9484	0.9475		cios	0.8898	0.9058	0.9500	0.9482	0.9500	0.9491
sse	0.0699	0.0704	0.0704	0.0708	0.0703	0.0708		sse	0.0707	0.0712	0.0704	0.0709	0.0703	0.0708
ese	0.0698	0.0704	0.0703	0.0709	0.0702	0.0705		ese	0.0695	0.0712	0.0701	0.0707	0.0701	0.0703
rse	0.0695	0.0708						rse	0.0701	0.0800
	; ;								; ;
bias	0.0002	0.0020	0.0002	0.0020	0.0001	0.0005		bias	0.0353	0.0304	0.0001	0.0019	0.0000	0.0004
cr	0.9542	0.9534	0.9532	0.9530	0.9532	0.9529		cr	0.8577	0.9224	0.9519	0.9511	0.9521	0.9529
mae	0.0320	0.0321	0.0320	0.0322	0.0320	0.0321		mae	0.0440	0.0413	0.0320	0.0321	0.0320	0.0321
cios	0.9500	0.9494	0.9494	0.9488	0.9494	0.9491		cios	0.8292	0.8629	0.9500	0.9494	0.9500	0.9497
sse	0.0400	0.0401	0.0401	0.0402	0.0400	0.0401		sse	0.0404	0.0406	0.0400	0.0401	0.0400	0.0401
ese	0.0401	0.0403	0.0403	0.0404	0.0402	0.0403		ese	0.0400	0.0404	0.0402	0.0403	0.0401	0.0402
rse	0.0401	0.0403						rse	0.0405	0.0455

cr: coverage rate; mae: mean absolute error; cios: confidence interval overlap statistics; sse: sample standard error; ese: estimated standard error; rse: robust standard error estimate.