Part 4: Power and Sample Size

Explores power and sample size for group-randomized trials (GRTs) with a focus on:

  • Cornfield's two penalties of extra variation and limited degrees of freedom (df)
  • Strategies to reduce extra variation and increase df
  • The seven steps involved in any power analysis
  • Estimating the intraclass correlation coefficient (ICC)
  • Adaptations required for unbalanced designs

The course also provides an example of a sample size calculation for a simple GRT.

Recorded on September 15, 2016

Interested in more information about power and sample size for GRTs?

Visit NIH's Research Methods Resources website for
a list of publications on sample size estimation methods
and a sample size calculator for GRTs. If you'd like a
demonstration of how to use the sample size calculator,
check out this Mind the Gap webinar.