JSM Preliminary Online Program
This is the preliminary program for the 2007 Joint Statistical Meetings in Salt Lake City, Utah.

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Activity Number: 426
Type: Contributed
Date/Time: Wednesday, August 1, 2007 : 10:30 AM to 12:20 PM
Sponsor: Section on Statistics in Epidemiology
Abstract - #309987
Title: Assessing Baseline and Post-Baseline Effects in Repeated Measures Data Analyses: An Example Using Smoking Cessation Data
Author(s): Xiaolei Zhou*+ and Beth Sherrill and Jianmin Wang
Companies: RTI International and RTI International and RTI Health Solutions
Address: 3040 Cornwallis Road, Durham, NC, 27703,
Keywords: repeated measures ; time interaction ; time-dependent variables
Abstract:

In behavior modification studies dynamically changing factors have complex effects on subsequent actions. The question is how to accommodate baseline and post-baseline factors in one flexible model and assess effects on outcomes that are of clinical relevance. For example, in a longitudinal study about smoking relapse, potential predictors for successful smoking cessation include: nicotine dependence, mood disturbance, and weight change. Several models could be fit to the data depending on the clinical question of interest; often in exploratory analyses, however, several models are fit to the data. This presents a particular challenge to the analyst if competing inferences are made. We developed a single flexible model that can be used to test a variety of null hypotheses, thus providing the analyst a more efficient tool for evaluating complex time-varying covariates.


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Revised September, 2007