American Statistical Association
New York City
Metropolitan Area Chapter

Virtual Seminar
Friday, September 16, 2022
12:00 - 1:00 PM (ET)

The New York Metro Area Chapter of the American Statistical Association

Is Pleased to Invite You to a Virtual Seminar On

Shared Parameter Mixed-Effects Location Scale Models for Intensive Longitudinal Data


Donald Hedeker
University of Chicago


Intensive longitudinal data are increasingly encountered in many research areas. For example, ecological momentary assessment (EMA) and/or mobile health (mHealth) methods are often used to study subjective experiences within changing environmental contexts. In these studies, up to 30 or 40 observations are usually obtained for each subject over a period of a week or so, allowing one to characterize a subject's mean and variance and specify models for both. In this presentation, we focus on an adolescent smoking study using EMA where interest is on characterizing changes in mood variation. We describe how covariates can influence the mood variances and also extend the statistical model by adding a subject-level random effect to the within-subject variance specification. This permits subjects to have influence on the mean, or location, and variability, or (square of the) scale, of their mood responses. The random effects are then shared in a modeling of future smoking levels. These mixed-effects location scale models have useful applications in many research areas where interest centers on the joint modeling of the mean and variance structure.

About the Speaker

Donald Hedeker's chief expertise is in the development and use of advanced statistical methods for clustered and longitudinal data, with particular emphasis on mixed-effects models. He is the primary author of several freeware computer programs for mixed-effects analysis. With Robert Gibbons, Don is the author of the text "Longitudinal Data Analysis," published by Wiley in 2006. More recently, he has developed methods and software for analysis of intensive longitudinal data, which are data with many measurements over time, often collected using mobile devices and/or the internet. Such data are increasingly obtained by researchers in many research areas, for example in the areas of mobile health (mHealth) and ecological momentary assessment (EMA) studies. He is an associate editor for Statistics in Medicine.

Presentation Slides

Date and Time
Friday, September 16, 2022
12:00 - 1:00 P.M. (ET)

Virtual Zoom Webinar
The Zoom link will be sent to all registered attendees
within three days of the event.

Registration and Fees
There is no fee but advanced registration is required.

Registration Deadline
Registration closed Tuesday, September 13, 2022.

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