Table 5.

Comparison of the non-stratified and stratified log-rank type test for different effect sizes: power

	62% events due to ex. haz.		93% events due to ex. haz.
	LRt	LRt-str	LRt	LRt-str
X∈D, bal (sex); S∉D, bal, bin, ef 0	0.505	0.505	0.870	0.870
X∈D, bal (sex); S∉D, bal, bin, ef 2x	0.502	0.519	0.863	0.880
X∈D, bal (sex); S∉D, bal, bin, ef 5x	0.465	0.559	0.778	0.894
X∈D, bal (sex); S∉D, bal, 10str, ef 0	0.495	0.496	0.879	0.875
X∈D, bal (sex); S∉D, bal, 10str, ef 2x	0.486	0.499	0.862	0.878
X∈D, bal (sex); S∉D, bal, 10str, ef 5x	0.472	0.559	0.772	0.895

Methods included: non-stratified (LRt) and stratified log-rank type test (LRt-str). (bal = balanced variable, i.e., the groups occur with equal probabilities; bin= binary variable; 10 str = 10 strata; ef= variable’s effect). X is the categorical covariate of interest, S the stratification covariate, D denotes the demographic variables