Analysing repeated measurements data: a practical comparison of methods
β Scribed by Rumana Z. Omar; Eileen M. Wright; Rebecca M. Turner; Simon G. Thompson
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 149 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0277-6715
No coin nor oath required. For personal study only.
β¦ Synopsis
A variety of methods are available for analysing repeated measurements data where the outcome is continuous. However, there is little information on how established methods, such as summary statistics and repeated measures analysis of variance (RMAOV), compare in practice with methods that have become available to applied statisticians more recently, such as marginal models (based on generalized estimating equation methodology) and multilevel models (that is, hierarchical random e!ects models). The aim of this paper is to exemplify the use of these methods, and directly compare their results by application to a clinical trial data set. The focus is on practical aspects rather than technical issues. The data considered were taken from a clinical trial of treatments for asthma in 240 children, in which a baseline and four post-randomization measurements of outcomes were taken. The simplicity of the method of summary statistics using the post-randomization mean of observations provided a useful initial analysis. However, "xed time e!ects or treatment}time interactions cannot be included in such an analysis, and choice of appropriate weighting when there is substantial missing data is problematic. RMAOV, marginal models and multilevel models generally provided similar estimates and standard errors for the treatment e!ects, although in one example with a relatively complex variance structure the marginal model produced less e$cient estimates. Two advantages of multilevel models are that they provide direct estimates of variance components which are often of interest in their own right, and that they can be naturally extended to handle multivariate outcomes.
π SIMILAR VOLUMES
This paper considers five methods of analysis of longitudinal assessment of health related quality of life (QOL) in two clinical trials of cancer therapy. The primary difference in the two trials is the proportion of participants who experience disease progression or death during the period of QOL a
In many clinical trials, treatment e$cacy is based upon response to a biological marker that is measured repeatedly during the course of follow-up. However, in some of these trials it is not clear, a priori, how treatment e!ects on the marker may manifest themselves or what kinds of e!ects are clini
In this paper we study a class of non-parametric statistics for comparing diagnostic markers with repeated measurements. Using adapted de"nitions of speci"city and sensitivity, we suggest methods to compare the average of sensitivities across all speci"cities or a range of speci"cities. The theory a