powerSignificanceInterim: Interim power of a replication study

In ReplicationSuccess: Design and Analysis of Replication Studies

Description

Computes the power of a replication study taking into account data from an interim analysis.

Usage

powerSignificanceInterim(zo, zi, c = 1, f = 1/2,
                         level = 0.025, 
                         designPrior = "conditional",
                         analysisPrior = "flat", 
                         alternative="greater", 
                         shrinkage = 0)

Arguments

zo	A vector of z-values from original studies.
zi	A vector of z-values from interim analyses of replication studies.
c	Ratio of the sample size of the replication study to the sample size of the original study.
f	Fraction of the replication study already completed.
level	The significance level.
designPrior	Either "conditional", "informed predictive" or "predictive". Defaults to "conditional". "informed predictive" refers to an informative normal prior coming from the original study. "predictive" refers to a flat prior.
analysisPrior	Either "flat" or "original". Defaults to "flat".
alternative	Either "less", "greater", or "two.sided". Defaults to "greater". Specifies direction of the alternative.
shrinkage	A number in [0,1]. Defaults to 0. Specifies how much the original effect estimate is shrunken towards zero (e.g. the effect is shrunken by a factor of 25% for shrinkage = 0.25).

Details

This is an extension of PowerSignificance() and adapts the ‘interim power’ from section 6.6.3 of Spiegelhalter et al. (2004) to the setting of replication studies.

Author(s)

Charlotte Micheloud

References

Spiegelhalter, D. J., Abrams, K. R., and Myles, J. P. (2004). Bayesian Approaches to Clinical Trials and Health-Care Evaluation, volume 13. John Wiley & Sons

Micheloud, C., Held, L. (2020). Power Calculations for Replication Studies. https://arxiv.org/abs/2004.10814

See Also

sampleSizeSignificance, powerSignificance

Examples

powerSignificanceInterim(zo = 2, zi = 2, c = 1, f = 1/2, 
                         designPrior = "conditional", 
                         analysisPrior = "flat")

powerSignificanceInterim(zo = 2, zi = 2, c = 1, f = 1/2, 
                         designPrior = "informed predictive", 
                         analysisPrior = "flat")

powerSignificanceInterim(zo = 2, zi = 2, c = 1, f = 1/2,
                        designPrior = "predictive", 
                        analysisPrior = "flat")

powerSignificanceInterim(zo = 2, zi = -2, c = 1, f = 1/2, 
                         designPrior = "conditional", 
                         analysisPrior = "flat")

powerSignificanceInterim(zo = 2, zi = 2, c = 1, f = 1/2, 
                         designPrior = "conditional", 
                         analysisPrior = "flat", 
                         shrinkage = 0.25)

ReplicationSuccess documentation built on Dec. 2, 2020, 3 p.m.