sim_data {BioPETsurv} | R Documentation |

This function simulates biomarkers and generates survival observations depending on biomarker values. The simulated data can be used to explore prognostic enrichment using `surv_enrichment`

.

sim_data(n = 500, biomarker = "normal", effect.size = 1.25, baseline.hazard = "constant", end.time = 10, end.survival = 0.5, shape = NULL, seed = 2333)

`n` |
The number of observations to simulate. |

`biomarker` |
Character specifying the shape of the biomarker distribution. Choices are |

`effect.size` |
The hazard ratio corresponding to one standard deviation increment in the biomarker. |

`baseline.hazard` |
Character ("constant"/"increasing"/"decreasing") specifying whether the overall hazard in the population is constant, increasing or decreasing over time. |

`end.time` |
The length of observation in the simulated dataset. In the data simulation, any events after this time will be censored at this time. |

`end.survival` |
The survival rate in the population at the end of observation. |

`shape` |
(Optional) the Weibull shape parameter for the baseline hazard. Values smaller and larger than 1 correspond to decreasing and increasing respectively. |

`seed` |
(Optional) specify the random seed used for simulation. |

The biomarker will be simulated from a standardized normal or lognormal distribution. It is important that `effect.size`

should correspond to a 1 SD increment in the biomarker. Conditioning on the biomarker values and assuming proportional hazards, survival times are simulated from a Weibull distribution with user-specified shape parameter, and the scale parameter is determined by the specified event rate and effect size.

Returns a list of the following items:

`data` |
A data frame with 4 columns: the value of biomarker, observed event time, event indicator and the true event time. |

`km.plot` |
The Kaplan-Meier survival curves of the simulated dataset at enrichment levels 0, 25%, 50% and 75%. |

## Simulate a dataset with 500 observations, ## where the biomarker is Normally distributed (with SD=1). ## The hazard ratio corresponding to every one unit of increament in the biomarker is 1.25. ## The observation period is 10 months, ## and the survival probability of the population at the end of observation is 0.5. ## Hazards are constant over time. sim_obj <- sim_data(n = 500, biomarker = "normal", effect.size = 1.25, baseline.hazard = "constant", end.time = 10, end.survival = 0.5) dat <- sim_obj$data

[Package *BioPETsurv* version 0.1.0 Index]