Analyzing change: a primer on multilevel models with applications
to nephrology.
American journal of nephrology, 28 (5):
792--801 (May 2008)Abstract
The analysis of change is central to the study of kidney research.
In the past 25 years, newer and more sophisticated methods for the
analysis of change have been developed; however, as of yet these
newer methods are underutilized in the field of kidney research.
Repeated measures ANOVA is the traditional model that is easy to
understand and simpler to interpret, but it may not be valid in complex
real-world situations. Problems with the assumption of sphericity,
unit of analysis, lack of consideration for different types of change,
and missing data, in the repeated measures ANOVA context are often
encountered. Multilevel modeling, a newer and more sophisticated
method for the analysis of change, overcomes these limitations and
provides a better framework for understanding the true nature of
change. The present article provides a primer on the use of multilevel
modeling to study change. An example from a clinical study is detailed
and the method for implementation in SAS is provided.
Copyright 2008 S. Karger AG, Basel.