getDesignFisher {rpact}

Get Design Fisher

Description

Performs Fisher's combination test and returns critical values for this design.

Usage

getDesignFisher(
  ...,
  kMax = NA_integer_,
  alpha = NA_real_,
  method = c("equalAlpha", "fullAlpha", "noInteraction", "userDefinedAlpha"),
  userAlphaSpending = NA_real_,
  alpha0Vec = NA_real_,
  informationRates = NA_real_,
  sided = 1,
  bindingFutility = NA,
  tolerance = 1e-14,
  iterations = 0,
  seed = NA_real_
)

Arguments

...

Ensures that all arguments (starting from the "...") are to be named and that a warning will be displayed if unknown arguments are passed.

kMax

The maximum number of stages K. Must be a positive integer of length 1 (default value is 3). The maximum selectable kMax is 20 for group sequential or inverse normal and 6 for Fisher combination test designs.

alpha

The significance level alpha, default is 0.025. Must be a positive numeric of length 1.

method

"equalAlpha", "fullAlpha", "noInteraction", or "userDefinedAlpha", default is "equalAlpha" (for details, see Wassmer, 1999).

userAlphaSpending

The user defined alpha spending. Numeric vector of length kMax containing the cumulative alpha-spending (Type I error rate) up to each interim stage: 0 <= alpha_1 <= ... <= alpha_K <= alpha.

alpha0Vec

Stopping for futility bounds for stage-wise p-values.

informationRates

The information rates t_1, ..., t_kMax (that must be fixed prior to the trial), default is (1:kMax) / kMax. For the weighted inverse normal design, the weights are derived through w_1 = sqrt(t_1), and w_k = sqrt(t_k - t_(k-1)). For the weighted Fisher's combination test, the weights (scales) are w_k = sqrt((t_k - t_(k-1)) / t_1) (see the documentation).

sided

Is the alternative one-sided (1) or two-sided (2), default is 1. Must be a positive integer of length 1.

bindingFutility

If bindingFutility = TRUE is specified the calculation of the critical values is affected by the futility bounds (default is TRUE).

tolerance

The numerical tolerance, default is 1e-14.

iterations

The number of simulation iterations, e.g., getDesignFisher(iterations = 100000) checks the validity of the critical values for the design. The default value of iterations is 0, i.e., no simulation will be executed.

seed

Seed for simulating the power for Fisher's combination test. See above, default is a random seed.

Details

getDesignFisher() calculates the critical values and stage levels for Fisher's combination test as described in Bauer (1989), Bauer and Koehne (1994), Bauer and Roehmel (1995), and Wassmer (1999) for equally and unequally sized stages.

Value

Returns a TrialDesign object. The following generics (R generic functions) are available for this result object:

• names() to obtain the field names,

• print() to print the object,

• summary() to display a summary of the object,

• plot() to plot the object,

• as.data.frame() to coerce the object to a data.frame,

• as.matrix() to coerce the object to a matrix.

How to get help for generic functions

Click on the link of a generic in the list above to go directly to the help documentation of the rpact specific implementation of the generic. Note that you can use the R function methods to get all the methods of a generic and to identify the object specific name of it, e.g., use methods("plot") to get all the methods for the plot generic. There you can find, e.g., plot.AnalysisResults and obtain the specific help documentation linked above by typing ?plot.AnalysisResults.

See Also

getDesignSet() for creating a set of designs to compare.

Other design functions: getDesignCharacteristics(), getDesignConditionalDunnett(), getDesignGroupSequential(), getDesignInverseNormal(), getGroupSequentialProbabilities(), getPowerAndAverageSampleNumber()

Examples

# Calculate critical values for a two-stage Fisher's combination test 
# with full level alpha = 0.05 at the final stage and stopping for 
# futility bound alpha0 = 0.50, as described in Bauer and Koehne (1994). 
getDesignFisher(kMax = 2, method = "fullAlpha", alpha = 0.05, alpha0Vec = 0.50)