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Krista Opsahl-Ong

3 accepted papers

2026

GEPA: Reflective Prompt Evolution Can Outperform Reinforcement Learning

ICLR 2026oral

Large language models (LLMs) are increasingly adapted to downstream tasks via reinforcement learning (RL) methods like Group Relative Policy Optimization (GRPO), which often require thousands of rollouts to learn new tasks. We argue that the interpretable nature of language often provides a much ric…

Cited by 0SourcecodeScholar
2024

Optimizing Instructions and Demonstrations for Multi-Stage Language Model Programs

EMNLP 2024main

Language Model Programs, i.e. sophisticated pipelines of modular language model (LM) calls, are increasingly advancing NLP tasks, but they require crafting prompts that are jointly effective for all modules. We study prompt optimization for LM programs, i.e. how to update these prompts to maximize a…

2022

Diagnosing failures of fairness transfer across distribution shift in real-world medical settings

NeurIPS 2022accept

Diagnosing and mitigating changes in model fairness under distribution shift is an important component of the safe deployment of machine learning in healthcare settings. Importantly, the success of any mitigation strategy strongly depends on the \textit{structure} of the shift. Despite this, there h…

Cited by 74SourcePDFScholar