Power considerations for trials of two experimental arms versus a standard active control or placebo.

Journal Article (Journal Article)

The power of the two-experimental arm trial depends on three choices: (1) when one arm is dropped (if at all); (2) the final testing procedure, assuming no dropping; and (3) the sampling ratio for the three arms. Multiple-arm designs require critical values which were calculated using Mathematica. Power calculations were exact based on probabilities from binomial distributions. The "drop the loser" strategy is optimal for the primary endpoint. The equal sized two treated arm trial gives reasonable power for the primary as well as good power to select the best treated arm. The best power was provided by the 3:3:4 sampling, but it was only marginally better.

Full Text

Duke Authors

Cited Authors

  • Hasselblad, V

Published Date

  • October 2016

Published In

Volume / Issue

  • 25 / 5

Start / End Page

  • 1824 - 1835

PubMed ID

  • 24047599

Electronic International Standard Serial Number (EISSN)

  • 1477-0334

Digital Object Identifier (DOI)

  • 10.1177/0962280213503916


  • eng

Conference Location

  • England