Description Usage Arguments Details Author(s) References

These two functions are to predict the correlation between two weighted log-rank tests at certain time `t.star`

under either the null hypothesis (using `cor.0`

) or the alternative hypothesis (using `cor.1`

).

1 2 3 |

`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. |

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

`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. |

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

`eps` |
Change point. |

These two functions are designed to calculate the predicted correlation between the two weighted log-rank tests at time `t.star`

under the two hypotheses. The null hypothesis is an exponential distribution for both the treatment and control arms with hazard `lambda`

, while the alternative hypothesis has the control group following an exponential distribution with hazard `lambda`

, and the treatment group following a piece-wise exponential distribution with hazard `lambda`

before `eps`

, but a hazard `theta`

times `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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