getFutilityBounds: Get Futility Bounds

In rpact: Confirmatory Adaptive Clinical Trial Design and Analysis

Get Futility Bounds

Description

This function converts futility bounds between different scales such as z-value, p-value, conditional power, predictive power, reverse conditional power, and effect estimate.

Usage

getFutilityBounds(
  sourceValue,
  ...,
  sourceScale = c("zValue", "pValue", "conditionalPower", "condPowerAtObserved",
    "predictivePower", "reverseCondPower", "effectEstimate"),
  targetScale = c("zValue", "pValue", "conditionalPower", "condPowerAtObserved",
    "predictivePower", "reverseCondPower", "effectEstimate"),
  design = NULL,
  theta = NA_real_,
  information = NA_real_,
  naAllowed = FALSE
)

Arguments

sourceValue	A numeric vector representing the futility bounds in the source scale.
...	Ensures that all arguments (starting from the "...") are to be named and that a warning will be displayed if unknown arguments are passed.
sourceScale	Character. The scale of the input futility bounds. Must be one of "zValue", "pValue", "conditionalPower", "condPowerAtObserved", "predictivePower", "reverseCondPower", or "effectEstimate".
targetScale	Character. The scale to which the futility bounds should be converted. Must be one of "zValue", "pValue", "conditionalPower", "condPowerAtObserved", "predictivePower", "reverseCondPower", or "effectEstimate".
design	The trial design. Required if either the sourceScale or targetScale is "reverseCondPower" or if the conversion involves conditional or predictive power in a group sequential or Fisher design. Must be a one-sided two-stage group sequential design or Fisher's combination test design.
theta	Numeric. The assumed effect size under the alternative hypothesis.
information	Numeric vector of length 2. The information levels at the two stages.
naAllowed	Logical. Indicates if NA sourceValue are permitted. Default is FALSE.

Details

If the sourceScale and targetScale are the same, the function returns the input sourceValue without modification. Otherwise, the function is designed to convert between the specified scales.

Value

A numeric vector representing the futility bounds in the target scale, or NULL if the conversion is not implemented or yields no result.

See Also

getDesignGroupSequential(), getDesignInverseNormal(), getDesignFisher() for direct specification of futility bounds on different scales using the argument futilityBoundsScale.

Examples

## Not run: 
# Example with identical source and target scales
getFutilityBounds(
    sourceValue = c(0, 0.5),
    sourceScale = "zValue",
    targetScale = "zValue"
)

# Example with different scales
getFutilityBounds(
    design = getDesignGroupSequential(kMax = 2, typeOfDesign = "noEarlyEfficacy", alpha = 0.05),
    information = c(10, 10),
    sourceValue = 0.5,
    sourceScale = "condPowerAtObserved",
    targetScale = "pValue"
)

## End(Not run)

rpact documentation built on Dec. 16, 2025, 5:07 p.m.