Andrzej T Galecki, MD, PhD

• PhD, Institue of Mother and Child Care, Warsaw, Poland, 1987
• MD, Medical Academy of Warsaw, Warsaw, Poland, 1981
• MS, Department of Applied Mathematics of Technical University of Warsaw, Warsaw, Poland, 1977

My primary interests lie in developing computational methods for analyzing correlated and over dispersed data, which are frequently encountered in many fields of application, such as pharmacokinetic and pharmacodynamic (PK/PD studies, longitudinal studies, survey sampling and gene mapping in genetics studies. A class of models often considered in this context are hierarchical or mixed-effects models. These models are an extension of the regression models whereby random effects are introduced to describe between-subject variation.

My interests related to mixed effects models lie in:
1. An extension of mixed models which allows between-subject variation to be modeled as a mixture of underlying distributions.

2. Computational methods for PK/PD population studies. Here models are often expressed as a solution of a system of ordinary differential equations. To address these advanced problems, I developed a SAS/IML NLMEM and successfully used to analyze existing data. Specific application of these models occurs in population studies when intravenous glucose tolerance test (IVGTT) studies are used to evaluate glucose metabolism in patients.

3. Modeling covariance structure in the presence of two or more repeated factors. A class of models proposed in Galecki, 1994 has been implemented in PROC MIXED, which is part of commercial statistical software SAS, starting with version 6.12. The proposed class of covariance structures is especially useful for the joint modeling of several outcomes measured longitudinally.

My other research interests involve a wide range of methodological and practical aspects of research on elderly including study design and conducting study itself. I am involved in several large NIH funded projects including Design, Data and Biostatistics Core at the Claude D. Pepper Older Americans Independence Center.

Galecki, A. and Burzykowski, T., 2013. Linear Mixed-Effects Models Using R. A Step-by-Step Approach. Springer, New York, NY. https://link.springer.com/book/10.1007/978-1-4614-3900-4

West, B.T., Welch, K.B. and Galecki, A.T., 2022. Linear Mixed Models: A Practical Guide Using Statistical Software (Third Edition). Chapman and Hall/CRC. https://www.taylorfrancis.com/books/mono/10.1201/9781003181064/linear-mixed-models-brady-west-kathleen-welch-andrzej-galecki

Doria, A., Galecki, A.T., Spino, C., Pop-Busui, R., Cherney, D.Z., Lingvay, I., Parsa, A., Rossing, P., Sigal, R.J., Afkarian, M., Aronson, R. et al, 2020. Serum urate lowering with allopurinol and kidney function in type 1 diabetes. New England Journal of Medicine, 382(26), pp.2493-2503. https://www.nejm.org/doi/full/10.1056/NEJMoa1916624

Preisser, J.S., Galecki, A.T., Lohman, K.K. and Wagenknecht, L.E., 2000. Analysis of smoking trends with incomplete longitudinal binary responses. Journal of the American Statistical Association, 95(452), pp.1021-1031. https://www.tandfonline.com/doi/abs/10.1080/01621459.2000.10474299

Galecki, A.T., Ten Have, T.R. and Molenberghs, G., 2001. A simple and fast alternative to the EM algorithm for incomplete categorical data and latent class models. Computational statistics and data analysis, 35(3), pp.265-281. https://www.sciencedirect.com/science/article/abs/pii/S0167947300000153

Galecki, A.T., 1994. General class of covariance structures for two or more repeated factors in longitudinal data analysis. Communications in Statistics-Theory and Methods, 23(11), pp.3105-3119. https://www.tandfonline.com/doi/abs/10.1080/03610929408831436

Email: agalecki@umich.edu 
Office: 734-936-2138

Address: 
Institute of Gerontology Room 923
300 North Ingalls
Ann Arbor, MI 48109-2007