Sample size estimation for GEE method for comparing slopes in repeated measurements data.


Journal Article

Sample size calculation is an important component at the design stage of clinical trials. Controlled clinical trials often use a repeated measurement design in which individuals are randomly assigned to treatment groups and followed-up for measurements at intervals across a treatment period of fixed duration. In studies with repeated measurements, one of the popular primary interests is the comparison of the rates of change in a response variable between groups. Statistical models for calculating sample sizes for repeated measurement designs often fail to take into account the impact of missing data correctly. In this paper we propose to use the generalized estimating equation (GEE) method in comparing the rates of change in repeated measurements and introduce closed form formulae for sample size and power that can be calculated using a scientific calculator. Since the sample size formula is based on asymptotic theory, we investigate the performance of the estimated sample size in practical settings through simulations.

Full Text

Duke Authors

Cited Authors

  • Jung, S-H; Ahn, C

Published Date

  • April 30, 2003

Published In

Volume / Issue

  • 22 / 8

Start / End Page

  • 1305 - 1315

PubMed ID

  • 12687656

Pubmed Central ID

  • 12687656

International Standard Serial Number (ISSN)

  • 0277-6715

Digital Object Identifier (DOI)

  • 10.1002/sim.1384


  • eng

Conference Location

  • England