Create a class of milestone. A milestone means the time point to take an action, e.g., carrying out (futility, interim, final) analysis for adding/removing arms, or stopping a trial early. It can also be any more general time point where trial data is used in decision making or adaptation. For example, one can define a milestone for changing randomization scheme, sample size re-assessment, trial duration extension etc.
Public methods in this R6 class are used in developing
this package. Thus, we have to export the whole R6 class which exposures all
public methods. However, none of the public methods on this page is
useful to end users. Instead, refer to the
vignette
to learn how to define milestones when performing simulation using
TrialSimulator.
Methods
Method new()
initialize milestone
Usage
Milestones$new(name, type = name, trigger_condition, action = doNothing, ...)Arguments
namecharacter. Name of milestone.
typecharacter vector. Milestone type(s) (futility, interim, final), a milestone can be of multiple types. This is for information purpose so can be any string.
trigger_conditionfunction to check if this milestone should trigger. See vignette
Condition System for Triggering Milestones in a Trial.actionfunction to execute when the milestone triggers.
...(optional) arguments of
action.
Method set_dry_run()
set if dry run should be carried out for the milestone. For more details,
refer to Controller::run.
Method reset()
reset an milestone so that it can be triggered again. Usually, this is called before the controller of a trial can run additional replicates of simulation.
Method trigger_milestone()
trigger an milestone (always TRUE) and execute action accordingly. It calls Trial$get_data_lock_time() to lock data based on conditions implemented in Milestones$trigger_condition. If time that meets the condition cannot be found, Trial$get_data_lock_time() will throw an error and stop the program. This means that user needs to adjust their trigger_condition (e.g., target number of events (target_n_events) is impossible to reach).