General info

I received my Ph.D. in Statistics from the Department of Statistics at the University of North Carolina at Chapel Hill in 1987 under the direction of Raymond J. Carroll . My interests include statistical models and methods for analysis of longitudinal data, especially nonlinear mixed effects models; methods for handling missing and mismeasured data in statistical models; statistical methods for analysis of clinical trials and observational studies, including approaches for drawing causal inferences; pharmacokinetic and pharmacodynamic analysis; combining mechanistic mathematical and statistical modeling of disease progression to design treatment strategies and clinical trials; and statistical inference in general. In addition to my position here at NCSU, I have a position as Adjunct Professor of Biostatistics and Bioinformatics at Duke University, and I spend most Wednesdays at Duke Clinical Research Institute collaborating with clinicians and biostatisticians there on interesting problems in cardiovascular disease research.

Courses

• ST 511, Experimental Statistics for Biological Sciences I. I taught this course last in Spring 1997. Class notes (Beware: 339 pages!).

• ST 732, Applied Longitudinal Data Analysis. I taught this course last in Spring 2007. Visit the class web page for more info.

• ST 762, Nonlinear Models for Univariate and Multivariate Response. I taught this course in Fall 2007. Visit the class web page for more info.

• ST 810A, Preparation for Statistical Research. This course is meant to help graduate students to hone their oral and written communication skills and to introduce them to essential research resources, the world of publication, getting grants, tenure, applying for a position, and all the other fun stuff associated with a career in research. I taught this course in Spring 2005; the class web page is the place to visit for course info and handouts.

• ST 810Q, Inverse Problem Methodology in Complex Stochastic Models. This special topics class, which I taught in Fall 2002 with Tom Banks of the Center for Research in Scientific Computation at NCSU, introduced students in statistics and applied mathematics to the use of complex dynamical systems models in data analysis. The course was part of the Program on Inverse Problem Methodology in Complex Stochastic Models at SAMSI , headquartered in the NISS building in Research Triangle Park.

Disclaimer: Class notes are not guaranteed to be error-free. If you find what you think is an error, please notify me.

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Recent and forthcoming papers

• Tsiatis, A.A. and Davidian, M. (2008) Comment on the paper "Demystifying Double Robustness: A Comparison of Alternative Strategies for Estimating a Population Mean from Incomplete Data" by Joseph D.Y. Kang and Joseph L. Schafer. Statistical Science 22, 569-573 (paper and link to published version)

• Zhang, M., Tsiatis, A.A., and Davidian, M. (2008) Improving efficiency of inferences in randomized clinical trials using auxiliary covariates. Biometrics (final manuscript version, definitive published version, and supplementary materials).

• Tsiatis, A.A., Davidian, M., Zhang, M., and Lu, X. (2007) Covariate adjustment for two-sample treatment comparisons in randomized clinical trials: A principled yet flexible approach. Statistics in Medicine (final manuscript version, definitive published version).

• Zhang, M. and Davidian, M. (2007) "Smooth" semiparametric regression analysis for arbitrarily censored time-to-event data. Biometrics (final manuscript version, definitive published version, and supplementary materials)

• Rosenberg, E.S., Davidian, M., and Banks, H.T. (2007) Using mathematical modeling and control to develop structured treatment interruption strategies for HIV infection. Drug and Alcohol Dependence 88, S41-S51, Supplement issue on "Customizing Treatment to the Patient: Adaptive Treatment Strategies." (manuscript, definitive published version).

• Adams, B.M., Banks, H.T., Davidian, M., and Rosenberg, E.S. (2007) Model fitting and prediction with HIV treatment interruption data. Bulletin of Mathematical Biology 69, 563-584. (manuscript, definitive published version)

• Lin, J., Zhang, D., and Davidian, M. (2006) Smoothing spline-based score tests for proportional hazards models. Biometrics 62, 803-812. (final manuscript version; definitive published version)

• Huang, X., Stefanski, L.A., and Davidian, M. (2006) Latent-model robustness in structural measurement error models. Biometrika 93, 53-64. (final manuscript version; definitive published version)

• Davidian, M., Tsiatis, A.A., and Leon, S. (2005) Semparametric estimation of treatment effect in a pretest-posttest study with missing data (with discussion). Statistical Science 20, 261-301. (definitive published version; also available at the journal website). Also, a report of simulations not given in the paper.

• Lunceford, J.K. and Davidian, M. (2004) Stratification and weighting via the propensity score in estimation of causal treatment effects: A comparative study. Statistics in Medicine 23, 2937-2960. (final manuscript version; definitive published version)

• Tsiatis, A.A. and Davidian, M. (2004) An overview of joint modeling of longitudinal and time-to-event data. Statistica Sinica 14, 793-818. (final manuscript version; definitive published version)

• Li, E., Zhang, D., and Davidian, M. (2004) Conditional estimation for generalized linear models when covariates are subject-specific parameters in a mixed model for longitudinal measurements. Biometrics 60, 1-7. ( final manuscript version; definitive published version)

• Bodnar, L. M., Davidian, M., Siega-Riz, A.M., and Tsiatis, A.A. (2004) Marginal structural models for analyzing causal effects of time-dependent treatments: An application in perinatal epidemology. American Journal of Epidemiology 159, 926-934. (definitive published version)

• Davidian, M. and Giltinan, D.M. (2003) Nonlinear models for repeated measurements: An overview and update. Editor's Invited paper, Journal of Agricultural, Biological, and Environmental Statstics 8, 387-419. ( final manuscript version; definitive published version)

• Yeap, B.Y., Catalano, P.J., Ryan, L.M., and Davidian, M. (2003) Robust two-stage approach to repeated measurements analysis of chronic ozone exposure in rats. Journal of Agricultural, Biological, and Environmental Statstics 8, 438-454 (definitive published version)

• Leon, S., Tsiatis, A.A., and Davidian, M. (2003) Semiparametric estimation of treatment effect in a pretest-posttest study. Biometrics 59, 1046-1055. ( final manuscript version; definitive published version)

• Song, X., Davidian, M. , and Tsiatis, A.A. (2002) A semiparametric likelihood approach to joint modeling of longitudinal and time-to-event data. Biometrics 58, 742-753. ( final manuscript version; definitive published version)

• Song, X., Davidian, M. , and Tsiatis, A.A. (2002) An estimator for the proportional hazards model with multiple longitudinal covariates measured with error. Biostatistics 3, 511-528.(final manuscript versions ; definitive published version)

• Chen, J., Zhang, D., and Davidian, M. (2002). Generalized linear mixed models with flexible distributions of random effects for longitudinal data. Biostatistics 3, 347-360 (definitive published version)

• Lunceford, J., Davidian, M., and Tsiatis, A.A. (2002) Estimation of the survival distribution of treatment policies in two-stage randomization designs in clinical trials. Biometrics 58 48-57 (definitive published version)

• Tsiatis, A.A. , Davidian, M. , and McNeney, B. (2002) Multiple imputation methods for testing treatment differences in survival distributions with missing cause of failure. Biometrika 89, 238--244 (definitive published version)

• Zhang, D. and Davidian, M. (2001). Linear mixed models with flexible distributions of random effects for longitudinal data. Biometrics 57, 795-802 (definitive published version)

• Tsiatis, A.A. and Davidian, M. (2001). A semiparametric estimator for the proportional hazards model with longitudinal covariates measured with error. Biometrika 88, 447-458. (final manuscript version; definitive published version)

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Nonlinear Models for Repeated Measurement Data

With my long-time partner in crime David Giltinan, formerly Staff Scientist at Genentech, Inc., and now international man of leisure, I am co-author of Nonlinear Models for Repeated Measurement Data , published by Chapman and Hall in 1995. You can view the preface and table of contents here. You may order either through www.amazon.com or the publisher, Chapman & Hall/CRC Press. You can also order Measurement Error in Nonlinear Models, A Modern Perspective, Second Edition (2006) , also published by Chapman and Hall/CRC, the same way (through www.amazon.com or the publisher); one of the authors is our own Len Stefanski , along with Ray Carroll and David Ruppert (my former professors at UNC-CH).

In fact, you can order my spouse's book, Semiparametric Theory and Missing Data (2006), from the publisher, Springer, or from amazon.com.

David and I are too exhausted to do a second edition, so do not look for one anytime soon...

See the stellar reviews of our book in the June 1997 issue of Journal of the American Statistical Association and the September 1997 issue of Biometrics .

Selected data sets from the book are available here:

• Indomethacin data (Chapter 2)
• DNase data (Chapter 5)
• Theophylline data (Chapter 5)
• Phenobarbital data (Chapter 6)
• Quinidine data and documentation (Chapter 9)
• Argatroban data (Chapter 9)
• Soybean data (Chapter 11)
• Sweetgum tree data (Chapter 11)
• Earthquake data (Chapter 11)

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Longitudinal Data Analysis: A Handbook of Modern Statistical Methods

Garrett Fitzmaurice, Geert Verbeke, Geert Molenberghs , and I are co-editors of the forthcoming book Longitudinal Data Analysis, which is Volume 1 in the Chapman & Hall/CRC Press series of Handbooks of Modern Statistical Methods and which should be available in May 2008. The book includes integrated chapters written by leading authorities on modeling and analysis of longitudinal data. Look for it at the Chapman and Hall/CRC Press booth at a statistical conference near you. Here is the publisher's flyer, which has more information.

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Recent presentations

Click on the title for the slides.

• "Improving Efficiency of Iinferences in Randomized Clinical Trials Using Auxiliary Covariates." (given at Emory Univeristy, March 2008).

• "Mathematical-Statistical Modeling to Inform the Design of HIV Treatment Strategies and Clinical Trials" (given at the 2008 ENAR Spring Meeting, March 2008), which was the second half of a tag team presentation with my collaborator Eric Rosenberg (Eric's slides).

• "Mathematical-Statistical Modeling to Inform the Design of HIV Treatment Strategies and Clinical Trials" (given at the FDA/Industry Statistics Workshop, Crystal City, Virginia, September 2007).

• "An Introduction to Dynamic Treatment Regimes" (Janet L. Norwood Award Lecture, given at University of Alabama at Birmingham, September 2007; also given at the Georgia Chapter of the American Statistical Association, March 2008).

• "An Introduction to Dynamic Treatment Regimes" (given at the 2007 ISCB Conference, Alexandroupolis, Greece, July 2007). Also, here are Susan Murphy's slides and Butch Tsiatis' slides.

• "The Role of Statistical Principles in Quantitative Biomedical Modeling" (given at the Atlantic Coast Conference on Mathematics in the Life and Biological Sciences, Virginia Tech, May 2007).

• "An Introduction to Dynamic Treatment Regimes" (given at the 2007 ENAR Spring Meeting, March 2007).

• "Some New Methods for Latent Variable Models and Survival Analysis" (Bernard Greenberg Lecture IV, University of North Carolina at Chapel Hill, May 2006).

• "Inference for Dynamic Treatment Regimes for Two-Stage Clinical Trials (and More Generally)" (Bernard Greenberg Lecture III, University of North Carolina at Chapel Hill, May 2006; updated September 2006).

• "Introduction to Modeling and Analysis of Longitudinal Data" (Introductory Lecture Session at the 2006 ENAR Spring Meeting, March 2006).

• "Estimation of Survival Distributions for Treatment Regimes in Two Stage Oncology Trials" (given in the session on "Dynamic Treatment Regimes" at the Symposium on Causal Inference, Johns Hopkins Bloomberg School of Public Health, January 2006).

• "Double Robustness in the Estimation of Causal Treatment Effects" (given in EPID 369, Department of Epidemiology, UNC-Chapel Hill, February 2007).

• "Semiparametric Estimation of Treatment Effect in a Pretest-Posttest Study" (given at the University of Florida Statistics' 7th Annual Winter Workshop on Longitudinal Data Analysis, Gainesville, Florida, January 2005; new version for Bernard Greenberg Lecture II, University of North Carolina at Chapel Hill, May 2006).

• "Nonlinear Mixed Effects Models: An Overview and Update" (given as part of the JABES Editor's session at the 2004 Interational Biometric Conference, Cairns, Queensland, Australia, July 2004).

• " What's in Between Dose and Response? Pharmacokinetics, Pharmacodynamics, and Statistics" (Myrto Lefkopoulou Lecture, Harvard School of Public Health, September 2003 and newer version Bernard Greenberg Lecture I, University of North Carolina at Chapel Hill, May 2006).

• "As Time Goes By - An Introduction to the Analysis of Longitudinal Data" (Introductory Overview Lecture given at the 2003 Joint Statistical Meetings in San Francisco, August 2003). See the ST 732 web page for my course notes on this topic.

• "Semiparametric Approaches to Inference in Joint Models for Longitudinal and Time-to-event Data" (given at the International Workshop on Statistical Modeling, Leuven, Belgium, July 2003).

• " As Time Goes By - An Introduction to Methods for the Analysis of Longitudinal Data" (given at the University of Florida, November 2002; this talk is less technical than the 2003 JSM talk above).

• "Semiparametric Mixed Effects Models with Flexible Random Effects Distribution" (given at the Nonparametric Statistics Conference, Crete, Greece, July 2002).

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Center for Quantitative Sciences in Biomedicine (CQSB)

I am Director of the Center for Quantitative Sciences in Biomedicine, a new NCSU research center focused on identifying and facilitating research that requires integration of expertise across the quantitative and biomedical/biological sciences. Scientists interested in pursuing research projects in this spirit and graduate students in Statistics, Applied Mathematics, and Biomathematics interested in training opportunities with the CQSB should contact me.

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Biostatistics @ NCSU

The Department of Statistics at NCSU hosts or is involved in several important biostatistics initiatives:

• Biostatistics Working Group -- This groups sponsors seminars and other activites in the Department on a regular basis.

• Summer Institute for Training in Biostatistics -- I am Co-Director with Dennis Boos of this wonderful training opportunity for undergraduates,which is a joint program with Duke Clinical Research Institute, supported by a grant from the National Heart, Lung, and Blood Institute (NHLBI).

• Integrated Biostatistical Training Program for CVD Research -- I am Director of this predoctoral training program, which is also joint with Duke Clinical Research Institute, supported by a T32 training grant from NHLBI.

• SAMSI Summer 2007 Program on Challenges in Dynamic Treatment Regimes and Multistage Decision-Making -- Susan Murphy and Butch Tsiatis, and I were Program Co-leaders for this SAMSI summer program, held in June 2007, which was meant to catalyze research on methodology for studying adaptive strategies for treating patients over time. Here we are at the poster session, where Susan and I demonstrated the extent of variation in footwear fashion seen during the program. See what you missed? The whole two weeks were just as fun!

  

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Biometrics

I am currently Executive Editor of Biometrics , the flagship journal of the International Biometric Society . The current Co-Editors are Geert Molenberghs , Naisyin Wang, and David Zucker. If you wish to send correspondence regarding Biometrics, please do not send it directly to me! Instead, send it to Ms. Ann Hanhart, the Biometrics Editorial Manager, at   biometrics@tibs.org.

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Miscellaneous

• Visit where I grew up.
• Visit my spouse.
• If you like shoes, once you have a pair of these, there's no turning back.

• Meet Kitty. Isn't she adorable?

  

• Here is a much more mature Kitty -- she's 19 and still going strong!

  

• Butch and I have been taking ballroom dancing lessons. We have a long way to go before we are ready for Dancing With the Stars. Here we are demonstrating how it's not done at the International Chinese Statistical Association Applied Statistics Symposium in Raleigh 2007...

  

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