American Statistical Association
New York City
Metropolitan Area Chapter

Mailman School of Public Health
Columbia University
Department of Biostatistics Colloquium



ANALYZING TRAJECTORIES:
FUNCTIONAL PREDICTORS OF UNIVARIATE RESPONSES

by

Ian McKeague
Columbia University


Abstract

In recent years, epidemiologists have embarked on numerous studies of early determinants of adult heath. It is increasingly believed that growth trajectories from gestation through childhood can have a profound impact on a range of adult health outcomes. A question of central interest is whether there are sensitive growth periods in childhood that influence adult health. Motivated by this question, this talk introduces a new type of functional regression model involving trajectories as predictors of univariate responses. The basic idea is to include time points among the parameters of interest, and to fit a (possibly misspecified) model using just the values of the trajectories at those times. This provides greater interpretability than the functional linear regression approach that has become popular in recent years, but creates an estimation problem with essentially infinite p and small n. The main result involves non-standard asymptotic theory: non-Gaussian limit distributions and rates of convergence that are drastically affected by the roughness of the trajectories and model misspecification. In the case of trajectories that are single-jump counting processes, it specializes to an existing type of change point analysis. Trajectories of diffusion type processes are examined in detail.


Date: Thursday, April 26, 2007
Time: 4:00 - 5:00 P.M.
Location: Mailman School of Public Health
Department of Biostatistics
722 West 168th Street
Judith Jansen Conference Room (Room 425)
New York, New York

RESERVATIONS ARE NOT REQUIRED

Refreshments will be served at 3:30 P.M. in the
Biostatistics Conference Room (Room 627).


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