Table 3.
Compare one-shot nonparametric method and IPCW method. Change point Cox PH model: covariates X and Y are generated from Uniform[0, 1]. Parameters in hazard function are λ0 = 0.01, β1 = 3, β20 = 0.1, and β21 = 15. The change point τ = 8.59 is selected such that CTX = CTY = 0.655 based on 100,000 simulations. The values of parameter λ for exponential censoring is chosen to achieve the desired censoring proportions. Threshold model: event time T is generated from exponential distribution with the rate λ =1. Two risk scores X and Y are generated from a mixture of bivariate normal distribution described in equation (7), with parameters μ0 = 2, ρ = 0, and . The cut point τ = 0.718 is selected such that CTX = CTY = 0.803 based on 100,000 simulations. Parameters λ for exponential censoring is chosen to achieve the desired censoring proportions. Sample size n=100.
The one-shot nonparametric method | The IPCW method | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
% Censor | ĈTX | ĈTY | ĈTX − ĈTY | % Reject H0 at α = 5% |
% Reject H0 at α = 10% |
C̃TX | C̃TY | C̃TX − C̃TY | % Reject H0 at α = 5% |
% Reject H0 at α = 10% |
|
n=100 | |||||||||||
| |||||||||||
Change point model | 0% | 0.657 | 0.660 | −0.003 | 5.0% | 9.8% | 0.661 | 0.659 | 0.002 | 4.6% | 9.1% |
10% | 0.663 | 0.647 | 0.016 | 6.4% | 11.8% | 0.661 | 0.659 | 0.002 | 4.2% | 8.3% | |
20% | 0.669 | 0.633 | 0.036 | 10.5% | 18.0% | 0.661 | 0.658 | 0.002 | 3.6% | 7.3% | |
33% | 0.68 | 0.612 | 0.068 | 21.9% | 31.6% | 0.661 | 0.659 | 0.002 | 2.7% | 5.7% | |
50% | 0.695 | 0.582 | 0.113 | 39.4% | 51.6% | 0.661 | 0.658 | 0.003 | 1.7% | 4.1% | |
65% | 0.710 | 0.563 | 0.147 | 47.2% | 59.5% | 0.663 | 0.657 | 0.006 | 1.3% | 3.1% | |
80% | 0.720 | 0.565 | 0.156 | 36.3% | 48.4% | 0.682 | 0.656 | 0.027 | 1.2% | 2.7% | |
| |||||||||||
Threshold model | 0% | 0.802 | 0.802 | 0.000 | 5.4% | 10.2% | 0.803 | 0.802 | 0.001 | 4.9% | 9.8% |
10% | 0.816 | 0.803 | 0.013 | 7.2% | 12.6% | 0.803 | 0.802 | 0.001 | 4.5% | 8.8% | |
20% | 0.830 | 0.805 | 0.025 | 10.7% | 18.0% | 0.803 | 0.802 | 0.001 | 3.8% | 7.5% | |
33% | 0.852 | 0.808 | 0.044 | 20.9% | 30.9% | 0.805 | 0.802 | 0.003 | 3.3% | 6.9% | |
50% | 0.884 | 0.818 | 0.066 | 40.0% | 52.4% | 0.809 | 0.803 | 0.006 | 2.1% | 5.2% | |
65% | 0.918 | 0.834 | 0.083 | 57.1% | 69.7% | 0.821 | 0.803 | 0.018 | 4.7% | 8.0% | |
80% | 0.955 | 0.865 | 0.090 | 65.5% | 77.8% | 0.863 | 0.802 | 0.061 | 10.2% | 17.6% |