Research

Constrained Learning for Causal Inference and Semiparametric Statistics

Tiffany Cai*, Yuri Fonseca*, Kaiwen Hou, Hongseok Namkoong (* denotes co-first authorship)

Paper link

Forthcoming

Poster at CODE@MIT 2024 and ACIC 2024

Summary We recast the problem of creating asymptotically efficient estimators for the average treatment effect as constrained optimization.

Posterior Sampling via Autoregressive Generation

Kelly Wang Zhang*, Tiffany Cai*, Hongseok Namkoong, Daniel Russo (* denotes co-first authorship)

Paper link

Poster at ICLR 2024 Workshop: Generative Models for Decision Making and talk at 2024 Economics and AI+ML Meeting

Summary We recast the problem of principled decision-making under uncertainty (Thompson Sampling) as autoregressive sequential modeling, trained via loss minimization.

Diagnosing Model Performance Under Distribution Shift

Tiffany Cai, Steve Yadlowsky, Hongseok Namkoong

Paper link, GitHub link

Under revision at Operations Research; presented at FORC 2023, INFORMS 2023

Summary When a model performs poorly out of distribution, how do we understand why performance became worse? We attribute change in model performance across distributions to X shifts and Y\|X shifts.

Tutorial: Modeling and Exploiting Data Heterogeneity under Distribution Shifts

Jiashuo Liu, Tiffany Cai, Peng Cui, Hongseok Namkoong

Tutorial link

Presented at NeurIPS 2023