# PwrGSD v2.3.1

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## Power in a Group Sequential Design

Tools for the evaluation of interim analysis plans for sequentially monitored trials on a survival endpoint; tools to construct efficacy and futility boundaries, for deriving power of a sequential design at a specified alternative, template for evaluating the performance of candidate plans at a set of time varying alternatives. See Izmirlian, G. (2014) <doi:10.4310/SII.2014.v7.n1.a4>.

## Functions in PwrGSD

 Name Description Haybittle The Haybittle method of Boundary Construction RR2RCM Relative risk to Relative Cumulative Mortality Power Extract the Power results Elements Create a subset of a "cpd.PwrGSD" object PwrGSD Calculate Power in a Group Sequential Design LanDemets The Lan-Demets method of Boundary Construction CRRtoRR Cumulative-risk ratios to risk ratios plot.cpd.PwrGSD Plot Method for cpd.PwrGSD objects CDFOR2LRR Convert CDF Odds Ratio to Logged Relative Risks CY2TOShaz Calender year rates to Study Year Rates ObrienFleming The O'Brien-Fleming Alpha Spending Function as.boundaries Convert a "PwrGSD" object to a "boundaries" object RCM2RR Relative cumulative mortality to Relative Risk lookup Lookup values for a piecewise constant function GrpSeqBnds Computes efficacy and futility boundaries Pow The Wang-Tsiatis Power Alpha Spending Function SimGSB Verifies the results of "GrpSeqBnds" via simulation wtdlogrank Weighted log-rank test lung Mayo Clinic Lung Cancer Data CondPower Conditional type I and type II error probabilities given current value of the test statistic gsd.dens A function for computing the probability density for the group sequentially monitored test statistic. DX A utility function for forming differences EX1gXK A function for computing the bias adjusted point estimate for a statistic observed to cross the efficacy boundary. IntSurvDiff Weighted Integrated Survival function test agghaz Aggregated Hazard paste The paste operator SCtoBdry Converts a stochastic curtailment boundary (conditional type I or II error probability) into a (efficacy or futility) boundary on the standardized Z scale cpd.PwrGSD Create a skeleton compound PwrGSD object mysurvfit My Survfit Pocock The Pocock Alpha Spending Function SC The Stochastic Curtailment method of Boundary Construction mystack Stack a dataset No Results!