Table 1.

Empirical type I error rates and empirical power for the robust log-rank tests unadjusted and adjusted for covariates: nominal type I error is 5%. λ = 0.25, exp(ψ) = 0.6. The Monte Carlo error is about 0.01.

		ρ = 0		ρ = 0.3		ρ = −0.3
${\sigma }_w^2$	θ	Adjusted	Unadjusted	Adjusted	Unadjusted	Adjusted	Unadjusted
Empirical type I error
0	0	0.056	0.057	0.052	0.054	0.058	0.060
	0.5	0.053	0.059	0.053	0.831	0.054	0.612
	−0.5	0.055	0.056	0.058	0.555	0.053	0.834
0.5	0	0.051	0.048	0.049	0.047	0.059	0.057
	0.5	0.046	0.049	0.055	0.575	0.051	0.435
	−0.5	0.048	0.058	0.058	0.452	0.057	0.584
1	0	0.051	0.060	0.055	0.056	0.059	0.058
	0.5	0.051	0.054	0.053	0.462	0.057	0.372
	−0.5	0.051	0.052	0.057	0.361	0.055	0.450
Empirical power
0	0	0.470	0.468	0.302	0.465	0.312	0.480
	0.5	0.524	0.453	0.404		0.281
	−0.5	0.531	0.460	0.279		0.362
0.5	0	0.367	0.368	0.243	0.379	0.221	0.376
	0.5	0.384	0.337	0.320		0.230
	−0.5	0.383	0.347	0.239		0.293
1	0	0.321	0.320	0.201	0.308	0.218	0.313
	0.5	0.321	0.286	0.209		0.213
	−0.5	0.302	0.275	0.221		0.206