American Statistical Association
New York City
Metropolitan Area Chapter

New York State Psychiatric Institute
at Columbia University Medical Center
Biostatistics Seminar



Yuanjia Wang, Ph.D.
Assistant Professor
Department of Biostatistics
Columbia University


It is known that standard methods for estimating the causal effect of a time-varying treatment on the mean of a repeated measures outcome (for example, GEE regression) may be biased when there are time-dependent variables that are simultaneously confounders of the effect of interest and are predicted by previous treatment. For this reason, inverse-probability of treatment weighted (IPTW) methods are developed in the literature of causal inference. In genetic studies, however, the main interest is to estimate or test the genetic effect rather than the treatment effect. In this work, we describe an IPTW method that provides unbiased estimate for the genetic effect, and propose a family-based association test using IPTW for family-based studies. By three examples and some simulations, we examine the magnitudes of bias in existing standard methods and compare them with the proposed methods. We apply the developed methods to systolic blood pressure data in the Framingham Heart Study, where some subjects took antihypertensive treatment during the course of study.

Biographical Note

Dr. Yuanjia Wang is currently an Assistant Professor in the Department of Biostatistics at Columbia University. She received her Ph.D. in Statistics from Columbia University in 2005. Dr. Wang's primary research interest is in statistical genetics with a focus on high-dimensional data analysis. With recent advance of technology in the fields of genetics and genomics, high throughput data are routinely generated and pose various challenges to their analyses. Dr. Wang's work involves developing efficient statistical methods and data mining tools to cope with large-scale data. Her other research interests include semi-parametric inference and functional data analysis.

Date: Tuesday, December 2, 2008
Time: 3:30 - 4:30 P.M.
Location: New York State Psychiatric Institute
1051 Riverside Drive
1st Floor - Room 1602
New York, New York


Refreshments will be served from 3:00 to 3:30 P.M.,
with a reception from 4:30 to 5:00 P.M.

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