...

Hi, I’m Walter Dempsey 👋

I am an Associate Professor of Biostatistics and an Associate Research Professor in the d3lab located in the Institute of Social Research at the University of Michigan. My research focuses on Statistical Methods for Digital and Mobile Health. I list my statistical papers below. A full publication list can be found on Google Scholar.

Contact Me

Education
  • ...
    University of Chicago

    Department of Statistics

    Ph.D.

  • ...
    University of Michigan

    Department of Statistics

    Postdoctoral Research Fellow

  • ...
    Harvard University

    Department of Statistics

    Postdoctoral Research Fellow

I list my statistical papers below. * indicates mentored student or postdoctoral fellow. A full publication list can be found on Google Scholar.

  1. Incorporating Auxiliary Variables to Improve the Efficiency of Time-Varying Treatment Effect Estimation
    Shi, J.*, Wu, Z., and Dempsey, W.
    Journal of the American Statistical Association 2025
  2. A meta-learning method for estimation of causal excursion effects to assess time-varying moderation
    Shi, J.*, and Dempsey, W.
    Biometrics 2025
  3. Selective inference for sparse graphs via neighborhood selection
    Huang, Y.*, Panigrahi, S., and Dempsey, W.
    Electronic Journal of Statistics 2025
  4. Non-Stationary Latent Auto-Regressive Bandits
    Trella, A., Dempsey, W., Doshi-Velez, F., and Murphy, S.
    Reinforcement Learning Journal 2025
  5. A Bayesian joint longitudinal-survival model with a latent stochastic process for intensive longitudinal data
    Abbott, M. R.*, Dempsey, W. H., Nahum-Shani, I., Potter, L. N., Wetter, D. W., Lam, C. Y., and Taylor, J. M. G.
    Biometrics 2025
  6. A Continuous-Time Dynamic Factor Model for Intensive Longitudinal Data Arising from Mobile Health Studies
    Abbott, M. R.*, Dempsey, W. H., Nahum-Shani, I., Lam, C. Y., Wetter, D. W., and Taylor, J. M. G.
    Psychometrika 2025
  7. Data integration methods for micro-randomized trials
    Huch, E.*, Nahum-Shani, I., Potter, L., Lam, C., Wetter, D. W., and Dempsey, W.
    Biometrics 2025
  8. RoME: A Robust Mixed-Effects Bandit Algorithm for Optimizing Mobile Health Interventions
    Huch, E.*, Shi, J.*, Abbott, M. R.*, Golbus, J. R., Moreno, A., and Dempsey, W. H.
    In Advances in Neural Information Processing Systems 2024
  9. A latent variable approach to jointly modeling longitudinal and cumulative event data using a weighted two-stage approach
    Abbott, M.*, Nahum-Shani, I., Lam, C., Wetter, D., and Dempsey, W.
    Statistics in Medicine 2024
  10. Exploring the Big Data Paradox for various estimands using vaccination data from the global COVID-19 Trends and Impact Survey (CTIS)
    Yang, Y.*, Dempsey, W., Han, P., Deshmukh, Y., Richardson, S., Tom, B., and Mukherjee, B.
    Science Advances 2024
  11. Node-Level Community Detection within Edge Exchangeable Models for Interaction Processes
    Zhang, Y.*, and Dempsey, W.
    Journal of the American Statistical Association 2024
  12. Recurrent Event Analysis in the Presence of Real-Time High Frequency Data via Random Subsampling
    Dempsey, W.
    Journal of Computational and Graphical Statistics 2023
  13. SMART Binary: New Sample Size Planning Resources for SMART Studies with Binary Outcome Measurements
    Dziak, J. J., Almirall, D., Dempsey, W., Stanger, C., and Nahum-Shani, I.
    Multivariate Behavioral Research 2024
  14. CataBEEM: Integrating Latent Interaction Categories in Node-wise Community Detection Models for Network Data
    Zhang, Y.*, and Dempsey, W.
    In Proceedings of the 40th International Conference on Machine Learning 2023
  15. Design of experiments with sequential randomizations on multiple timescales: the hybrid experimental design
    Nahum-Shani, I., Dziak, J., Venera, H.*, Pfammatter, A., Spring, B., and Dempsey, W.
    Behavior Research Methods 2024
  16. Addressing selection bias and measurement error in COVID-19 case count data using auxiliary information
    Dempsey, W.
    The Annals of Applied Statistics 2023
  17. Assessing time-varying causal effect moderation in the presence of cluster-level treatment effect heterogeneity and interference
    Shi, J.*, Wu, Z., and Dempsey, W.
    Biometrika 2023
  18. Kernel Deformed Exponential Families for Sparse Continuous Attention
    Moreno, A.*, Nagesh, S., Chatterjee, S., Wu, Z., Dempsey, W., and Rehg, J.
    In Advances in Neural Information Processing Systems 2022
  19. Optimal test allocation strategy for COVID-19
    Du, J., Beesley, L., Lee, S., Zhou, X., Dempsey, W., and Mukherjee, B.
    Statistics in Medicine 2021
  20. A Geometry-Driven Longitudinal Topic Model
    Wang, Y.*, Hougen, C., Oselio, B.*, Dempsey, W., and Hero, A.
    Harvard Data Science Review 2021
  21. Hierarchical edge exchangeable models for structured interaction networks
    Dempsey, W., Oselio, B.*, and Hero, A.
    Journal of the American Statistical Association 2021
  22. A Functional EM Algorithm for Panel Count Data with Missing Counts
    Moreno, A.*, Wu, Z., Wetter, D., Lam, C., Nahum-Shani, I., Dempsey, W., and Rehg, J.
    In Advances in Neural Information Processing Systems 2021
  23. Exchangeable Markov multi-state survival processes
    Dempsey, W.
    Statistica Sinica 2021
  24. A Statistical Framework for Modern Network Science
    Crane, H., and Dempsey, W.
    Statistical Science 2020
  25. The stratified micro-randomized trial design: Sample size considerations for testing nested causal effects of time-varying treatments
    Dempsey, W., Liao, P., Kumar, S., and Murphy, S. A.
    The Annals of Applied Statistics 2020
  26. Relational exchangeability
    Crane, H., and Dempsey, W.
    Journal of Applied Probability 2019
  27. Just-in-Time but Not Too Much: Determining Treatment Timing in Mobile Health
    Liao, P., Dempsey, W., Sarker, H., Hossain, S., al’Absi, M., Klasnja, P., and Murphy, S. A.
    Proc. ACM Interact. Mob. Wearable Ubiquitous Technol. 2018
  28. Survival Models and Health Sequences
    Dempsey, W., and McCullagh, P.
    Lifetime Data Analysis 2018
  29. Edge exchangeable models for interaction networks
    Crane, H., and Dempsey, W.
    Journal of the American Statistical Association 2018
  30. Weak continuity of predictive distribution for Markov survival processes
    Dempsey, W., and McCullagh, P.
    Electronic Journal of Statistics 2017
  31. iSurvive: An Interpretable, Event-time Prediction Model for mHealth
    Dempsey, W. H., Moreno, A.*, Scott, C. K., Dennis, M. L., Gustafson, D. H., Murphy, S. A., and Rehg, J. M.
    In Proceedings of the 34th International Conference on Machine Learning 2017
  32. Randomised trials for the Fitbit generation
    Dempsey, W., Liao, P., Klasnja, P., Nahum-Shani, I., and Murphy, S. A.
    Significance 2015
  33. Multiresolution analysis on the symmetric group
    Kondor, R., and Dempsey, W.
    In Advances in Neural Information Processing Systems 2012

Posts about Methods, Software, Tutorials, Lab Updates, and (sometimes) My Opinions/Side Projects.

Most recent post:

Evaluating Time-Varying Treatment Effects in Hybrid SMART-MRT Designs
methods

A statistical framework for jointly estimating synergistic and marginal causal effects when digital and human-delivered interventions operate at multiple timescales.

View all posts →

A list of recent courses that I have taught at the University of Michigan.

BIOSTAT617

01/01/2019 - 06/30/2023

Theory and Methods in Survey Design. Theory underlying sample designs and estimation procedures commonly used in survey practice. The latest version of the course can be found on Canvas

BIOSTAT629

08/30/2019 - 08/30/2020

Case Studies In Health Big Data. A project-based course that integrates all competencies learned in the Health Data Science Curriculum to provide a culminating research experience. Students work on two to three health big data projects, through which they learn to identify scientific objectives and analytical strategies and report findings through oral presentation and written documents. The latest version of the course can be found on Canvas

A list of recent graduate students and postdoctoral research fellows.

Yaxuan Huang
Yaxuan Huang
PhD Student in Biostatistics. Yaxuan's research focuses on developing reinforcement learning methods for decision-making with missing data. She is also interested in real-world deployment of these methods in online mobile health studies.
Rachel Tucker Gonzalez
Rachel Tucker Gonzalez
PhD Student in Biostatistics (with Phil Boonstra). Rachel's research interests include Bayesian nonparametric methods for multistate models, with applications to win ratio estimation. She is a member of the Cancer Biostatistics Training Program at the University of Michigan and works on a variety of applied projects across cancer sites.
Yuxuan Chen
Yuxuan Chen
PhD Student in Biostatistics. Works on selective inference to ensure valid statistical inference for effect moderation when models are chosen in a data-driven manner using micro-randomized trial data.
Tzu-Hsuan Lin
Tzu-Hsuan Lin
PhD Student in Biostatistics.
Youqi Yang
Youqi Yang
PhD Student in Biostatistics (with Bhramar Mukherjee). Research focuses on statistical methods for causal inference in mediation within micro-randomized trials, as well as treatment heterogeneity within randomized controlled trials.
Swaraj Bose
Swaraj Bose
PhD Student in Biostatistics. Research focuses on building prediction intervals for Individual Treatment Effects (ITEs) for Micro-randomized trials (MRTs) using conformal inference techniques for decision support.
Madeline Abbott
Madeline Abbott
Graduated, 2024. Research Associate in the Department of Biostatistics at Harvard University. F31 Grant Recipient, Best Presentation at MSSISS 2023. Worked on statistical methods for intensive longitudinal data arising from mobile health trials, specifically latent variable models and joint models with recurrent event processes.
Easton Huch
Easton Huch
Graduated, 2025. Postdoctoral Fellow in Quantitative Marketing at Johns Hopkins University. Worked on robust Bayesian methods for causal inference with applications to time-varying effect estimation in mobile health studies.
Hera Shi
Hera Shi
Graduated, 2023. Postdoctoral Research Fellow at the University of Cambridge with Qingyuan Zhao. Worked on statistical methods for time-varying treatment effects in the context of micro-randomized trials.
Yuhua Zhang
Yuhua Zhang
Graduated, 2023. Postdoctoral Research Fellow at Harvard University with Jukka-Pekka Onnela. Worked on statistical methods for network data.