
4
Sample Size Determination for Correlated
Outcome Measurements Using GEE
4.1 Motivation
Experimental designs that generate correlated measurements of an outcome
are widely used in biomedical, social, and behavioral studies. We usually clas-
sify such experimental designs into two types: clustered or longitudinal. In
a clustered trial, randomization is performed at the level of some aggregate,
such as schools, clinics, or communities. It is often adopted due to necessity
where the intervention under test is delivered on a group basis, for example, a
radio campaign against smoking in a socially and economically disadvantaged
community. It can also be employ ...