This class represents target data for time-to-event analysis. It inherits from the TargetData class.
The target trial follows the modified fixed-calendar design: patients enter
uniformly over an accrual window, each may be followed for at most
max_follow_up_time, and the database closes final_follow_up after the end
of recruitment. See R/simulation_time_to_event.R for the generator and the
Cox fit.
Super class
TargetData -> TimeToEventTargetData
Public fields
control_rateRate in the control arm of the target study
treatment_rateRate in the treatment arm of the target study
max_follow_up_timeMaximum individual follow-up time, L
accrual_periodLength of the recruitment window, A
final_follow_upTime from the end of recruitment to database closure, F
dropout_probabilityProbability of loss to follow-up over the maximum follow-up time
event_time_distributionEither "exponential" or "weibull"
weibull_shapeCommon Weibull shape parameter, q
weibull_scaleControl-arm Weibull scale, calibrated to the reported relapse-free probability
treatment_delayTime before the treatment effect starts, in years; 0 for proportional hazards
late_log_hrLog hazard ratio once the effect has started, chosen so that the Cox model's large-sample limit equals the treatment effect
Methods
Inherited methods
TimeToEventTargetData$new()
Initialize the TimeToEventTargetData object
Usage
TimeToEventTargetData$new(
source_data,
sampling_approximation,
target_sample_size_per_arm,
control_drift = 0,
treatment_drift,
summary_measure_likelihood,
max_follow_up_time,
accrual_period = NULL,
final_follow_up = NULL,
weibull_shape = NULL,
weibull_relapse_free_probability = NULL,
dropout_probability = 0,
event_time_distribution = "exponential",
treatment_delay = 0
)Arguments
source_dataThe source data used for generating the target data.
sampling_approximationA flag indicating whether to use sampling approximation.
target_sample_size_per_armThe target sample size per arm.
control_driftThe control drift.
treatment_driftThe treatment drift.
summary_measure_likelihoodThe summary measure distribution.
max_follow_up_timeThe maximum individual follow-up time.
accrual_periodThe length of the recruitment window.
final_follow_upThe time between the end of recruitment and database closure.
weibull_shapeThe common Weibull shape parameter.
weibull_relapse_free_probabilityThe control-arm relapse-free probability at the maximum follow-up time, used to calibrate the Weibull scale.
dropout_probabilityThe probability of loss to follow-up over the maximum follow-up time.
event_time_distributionEither "exponential" or "weibull".
treatment_delayTime before the treatment effect starts, in years. Zero, the default, is the proportional-hazards design.
TimeToEventTargetData$arm_parameters()
The event-time parameters of each arm: rates under the exponential model, scales under the Weibull model.
TimeToEventTargetData$generate()
This function generates target data based on the specified parameters.