Analysis of Observational Health Care Data Using SAS

Chapter 18

Sample Size Calculation for Observational Studies

Sin-Ho JungTaiyeong LeeElizabeth DeLong

Abstract

18.1 Introduction

18.2 Continuous Variables

18.3 Binary Variables

18.4 Two-Sample Log-Rank Test for Survival Data

18.5 Two-Sample Longitudinal Data

18.6 Discussion

Appendix: Asymptotic Distribution of Wilcoxon Rank Sum Test under H_a

References

 

Abstract

For a number of reasons, observational studies are currently being used to provide evidence to support medical decisions. Because these studies do not carry the same level of credibility conferred to randomized trials, appropriate attention to statistical issues is paramount. In particular, considerations of event rate, sample size, and power frequently occur. This chapter provides mechanisms ...