Description Usage Arguments Details Author(s) References See Also

Calulcation of the information/covariance based on a presumed survival function under the alternative hypothesis.

1 2 3 |

`rho` |
First power parameter for the Fleming-Harrington weight which weighs on the early departures: |

`gamma` |
Second power parameter for the Fleming-Harrington weight which weighs on the late departures: |

`lambda` |
Event hazard for the control arm. |

`theta` |
Hazard ratio after the change point (before the change point HR should be 1). |

`eps` |
Change point. |

`R` |
End of the accrual period. |

`p` |
Treatment assignment probability. |

`t.star` |
Time point we pause the study to check the cumulative information under the null. |

`rho1` |
First power parameters for the two Fleming-Harrington weights, defined for covariance calculation. |

`gamma1` |
Second power parameters for the two Fleming-Harrington weights, defined for covariance calculation. |

`rho2` |
First power parameters for the two Fleming-Harrington weights, defined for covariance calculation. |

`gamma2` |
Second power parameters for the two Fleming-Harrington weights, defined for covariance calculation. |

This function is prepared to calculate the predicted information/covariance purely based on the assumed survival function under the alternaitve hypothesis: the control group is following an exponential distribution with hazard `lambda`

, while the treatment group is following a piece-wise exponential distribution with same hazard before `eps`

, but a hazard equals `theta`

times the `lambda`

after `eps`

.

Lili Wang.

Hasegawa, T. (2016). Group sequential monitoring based on the weighted log‐rank test statistic with the Fleming–Harrington class of weights in cancer vaccine studies. Pharmaceutical statistics, 15(5), 412-419.

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