Description Usage Arguments Value References See Also Examples

Compute the baseline parameters *ζ_0^2* and *\boldsymbolδ_0*
needed for sample size calculation for standard win ratio test (see `WRSS`

).
The calculation is based
on a Gumbel–Hougaard copula model for survival time *D^{(a)}* and nonfatal event
time *T^{(a)}* for group *a* (1: treatment; 0: control):

*{P}(D^{(a)}>s, T^{(a)}>t) =\exp≤ft(-≤ft[≤ft\{\exp(aξ_1)λ_Ds\right\}^κ+
≤ft\{\exp(aξ_2)λ_Ht\right\}^κ\right]^{1/κ}\right),*

where *ξ_1* and *ξ_2* are the component-wise log-hazard ratios to be used
as effect size in `WRSS`

.
We also assume that patients are recruited uniformly over the period *[0, τ_b]*
and followed until time *τ* (*τ≥qτ_b*), with an exponential
loss-to-follow-up hazard *λ_L*.

1 |

`lambda_D` |
Baseline hazard |

`lambda_H` |
Baseline hazard |

`kappa` |
Gumbel–Hougaard copula correlation parameter |

`tau_b` |
Length of the initial (uniform) accrual period |

`tau` |
Total length of follow-up |

`lambda_L` |
Exponential hazard rate |

`N` |
Simulated sample size for monte-carlo integration. |

`seed` |
Seed for monte-carlo simulation. |

A list containing real number `zeta2`

for *ζ_0^2*
and bivariate vector `delta`

for *\boldsymbolδ_0*.

Mao, L., Kim, K. and Miao, X. (2021). Sample size formula for general win ratio analysis. Biometrics, https://doi.org/10.1111/biom.13501.

1 | ```
# see the example for WRSS
``` |

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