Sample Size Requirements and Study Duration for Testing Main Effects and Interactions in Completely Randomized Factorial Designs When Time to Event is the Outcome.


Journal Article

In this paper we develop the methodology for designing clinical trials with any factorial arrangement when the primary outcome is time to event. We provide a matrix formulation for calculating the sample size and study duration necessary to test any effect with a pre-specified type I error rate and power. Assuming that a time to event follows an exponential distribution, we describe the relationships between the effect size, the power, and the sample size. We present examples for illustration purposes. We provide a simulation study to verify the numerical calculations of the expected number of events and the duration of the trial. The change in the power produced by a reduced number of observations or by accruing no patients to certain factorial combinations is also described.

Full Text

Duke Authors

Cited Authors

  • Moser, BK; Halabi, S

Published Date

  • 2015

Published In

Volume / Issue

  • 44 / 2

Start / End Page

  • 275 - 285

PubMed ID

  • 25530661

Pubmed Central ID

  • 25530661

International Standard Serial Number (ISSN)

  • 0361-0926

Digital Object Identifier (DOI)

  • 10.1080/03610926.2012.705940


  • eng

Conference Location

  • United States