Research
My research spans several interconnected areas in statistics and biostatistics, with a unifying focus on addressing population heterogeneity to improve individual health outcomes. Below are the main themes of my work, with key publications from each area.
Causal Inference
Development of principled methods for estimating causal effects from observational data. Topics include weighting methods for continuous, binary, and nonstandard treatments, modified treatment policies, handling violations of positivity and other standard causal assumptions, methods for generalizability and transportability, estimating heterogeneous treatment effects, and more.
- Estimating causal effects of functional treatments with modified functional treatment policies Preprint (2026) [arXiv:2602.09145]
- Doss and Huling’s contribution to the Discussion of ‘Augmented balancing weights as linear regression’ by Bruns-Smith et al. Journal of the Royal Statistical Society Series B: Statistical Methodology (2026) [doi]
- A Framework for Causal Estimand Selection Under Positivity Violations Biometrics (2026) [arXiv:2410.12093] [doi]
- Partially Retargeted Balancing Weights for Causal Effect Estimation Under Positivity Violations Preprint (2025)★ Distinguished Student Paper Award, ENAR 2026[arXiv:2510.22072]
- Data adaptive covariate balancing for causal effect estimation for high dimensional data Preprint (2025) [arXiv:2512.18069]
- Exploring the effects of mechanical ventilator settings with modified vector-valued treatment policies Preprint (2025) [arXiv:2507.09809]
- Modified treatment policy effect estimation with weighted energy distance The Annals of Applied Statistics, 19(4):2555–2577 (2025)★ Distinguished Student Paper Award, ENAR 2024[arXiv:2310.11620] [doi]
- Causally interpretable meta-analysis combining aggregate and individual participant data American Journal of Epidemiology, 194(7):2060–2068 (2025)★ Distinguished Student Paper Award, ENAR 2024[doi]
- Independence weights for causal inference with continuous treatments Journal of the American Statistical Association, 119(546):1657–1670 (2024) [arXiv:2107.07086] [doi] [code] [CRAN]
- Energy balancing of covariate distributions Journal of Causal Inference (2024) [arXiv:2004.13962] [doi] [code]
- An intersectional framework for counterfactual fairness in risk prediction Biostatistics, 25(3):702–717 (2024) [arXiv:2210.01194] [doi] [code]
- Robust sample weighting to facilitate individualized treatment rule learning for a target population Biometrika, 111(1):309–329 (2024) [arXiv:2105.00581] [doi]
- Improving Precision of RCT-Based CATE Estimation using Data Borrowing with Double Calibration Preprint (2023) [arXiv:2306.17478]
Weighting Methods for Causal Inference
A central challenge in observational studies is confounding: because treatment is not randomly assigned, differences in outcomes across treatment groups may reflect pre-existing differences in patient characteristics rather than true causal effects. Weighting methods address this by reweighting the observed sample so that covariate distributions are balanced across groups, enabling valid causal comparisons. Classical propensity score approaches can be sensitive to model misspecification. I develop weighting approaches that are flexible, user-friendly, and robust to complex confounding. This includes energy balancing weights--a model-free method that directly minimizes distributional imbalance, requiring no tuning parameters and no secondary modeling decisions—-as well as independence weights for continuous-valued treatments, modified treatment policy estimators based on weighted energy distance, and more.
- A Framework for Causal Estimand Selection Under Positivity Violations Biometrics (2026) [arXiv:2410.12093] [doi]
- Partially Retargeted Balancing Weights for Causal Effect Estimation Under Positivity Violations Preprint (2025)★ Distinguished Student Paper Award, ENAR 2026[arXiv:2510.22072]
- Data adaptive covariate balancing for causal effect estimation for high dimensional data Preprint (2025) [arXiv:2512.18069]
- Modified treatment policy effect estimation with weighted energy distance The Annals of Applied Statistics, 19(4):2555–2577 (2025)★ Distinguished Student Paper Award, ENAR 2024[arXiv:2310.11620] [doi]
- Independence weights for causal inference with continuous treatments Journal of the American Statistical Association, 119(546):1657–1670 (2024) [arXiv:2107.07086] [doi] [code] [CRAN]
- Energy balancing of covariate distributions Journal of Causal Inference (2024) [arXiv:2004.13962] [doi] [code]
- Robust sample weighting to facilitate individualized treatment rule learning for a target population Biometrika, 111(1):309–329 (2024) [arXiv:2105.00581] [doi]
Precision Medicine & Heterogeneity of Treatment Effect
Statistical methods for personalizing treatment decisions based on individual patient characteristics and understanding heterogeneity of treatment effect. This includes estimation of optimal individualized treatment rules, subgroup identification, and conditional average treatment effects. Includes methods for complex outcome types, multi-category treatments, and high-dimensional data.
- An effective framework for estimating individualized treatment rules with multi-category treatments Advances in Neural Information Processing Systems (NeurIPS) (2024) [doi]
- Robust sample weighting to facilitate individualized treatment rule learning for a target population Biometrika, 111(1):309–329 (2024) [arXiv:2105.00581] [doi]
- Improving Precision of RCT-Based CATE Estimation using Data Borrowing with Double Calibration Preprint (2023) [arXiv:2306.17478]
- A reluctant additive model framework for interpretable nonlinear individualized treatment rules The Annals of Applied Statistics, 17(4):3384–3402 (2023) [doi]
Evidence Synthesis, Generalizability, Transportability, & Data-Fusion
Methods for combining evidence and data across multiple studies while preserving causal interpretability. This includes causally interpretable random-effects meta-analysis, methods combining aggregate and individual participant data from randomized trials when targeting a target population, and transportability of causal effects to target populations in the presence of patient nonadherence.
- Partially Retargeted Balancing Weights for Causal Effect Estimation Under Positivity Violations Preprint (2025)★ Distinguished Student Paper Award, ENAR 2026[arXiv:2510.22072]
- Causally interpretable meta-analysis combining aggregate and individual participant data American Journal of Epidemiology, 194(7):2060–2068 (2025)★ Distinguished Student Paper Award, ENAR 2024[doi]
- Robust sample weighting to facilitate individualized treatment rule learning for a target population Biometrika, 111(1):309–329 (2024) [arXiv:2105.00581] [doi]
- Improving Precision of RCT-Based CATE Estimation using Data Borrowing with Double Calibration Preprint (2023) [arXiv:2306.17478]
Population Heterogeneity & Risk Prediction
Methods for modeling and leveraging population heterogeneity in statistical analyses and for clinical risk prediction. This work focuses on the development of statistical modeling approaches that tailor predictions and analyses in the presence of population heterogeneity instead of one-size-fits-all modeling approaches. intervention effects.
- Heterogeneity-Aware Regression with Nonparametric Estimation and Structured Selection for Hospital Readmission Prediction Preprint (2025) [arXiv:2507.06388]
- An intersectional framework for counterfactual fairness in risk prediction Biostatistics, 25(3):702–717 (2024) [arXiv:2210.01194] [doi] [code]
- Doubly structured sparsity for grouped multivariate responses with application to functional outcome score modeling Statistics in Medicine, 42(15):2619–2636 (2023) [arXiv:2302.11098] [doi] [code]
- Sufficient dimension reduction for populations with structured heterogeneity Biometrics, 78(4):1626–1638 (2022) [arXiv:2212.12394] [doi] [code] [CRAN]
High-Dimensional & Computational Methods
Variable selection and dimensionality reduction for complex, high-dimensional data, and efficient computational algorithms for large-scale statistical problems. This includes fast penalized regression, structured sparsity approaches, and optimization algorithms for large datasets.
- Data adaptive covariate balancing for causal effect estimation for high dimensional data Preprint (2025) [arXiv:2512.18069]
- Heterogeneity-Aware Regression with Nonparametric Estimation and Structured Selection for Hospital Readmission Prediction Preprint (2025) [arXiv:2507.06388]
- A reluctant additive model framework for interpretable nonlinear individualized treatment rules The Annals of Applied Statistics, 17(4):3384–3402 (2023) [doi]
- Doubly structured sparsity for grouped multivariate responses with application to functional outcome score modeling Statistics in Medicine, 42(15):2619–2636 (2023) [arXiv:2302.11098] [doi] [code]
- Sufficient dimension reduction for populations with structured heterogeneity Biometrics, 78(4):1626–1638 (2022) [arXiv:2212.12394] [doi] [code] [CRAN]
- Fast penalized regression and cross validation for tall data with the {oem} package Journal of Statistical Software, 104(6):1–24 (2022) [arXiv:1801.09661] [doi] [code] [CRAN]
- Selection and estimation optimality in high dimensions with the TWIN penalty Preprint (2021) [arXiv:1806.01936]
Health Systems Applications
Applications of statistical methods to improve healthcare delivery and patient outcomes, including hospital risk prediction, readmission reduction, and personalized clinical intervention recommendations.
- Heterogeneity-Aware Regression with Nonparametric Estimation and Structured Selection for Hospital Readmission Prediction Preprint (2025) [arXiv:2507.06388]
- Doubly structured sparsity for grouped multivariate responses with application to functional outcome score modeling Statistics in Medicine, 42(15):2619–2636 (2023) [arXiv:2302.11098] [doi] [code]