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Jean Kaddour

I'm a research scientist at Google DeepMind, working on the science of post-training. My research has spanned:

Before GDM, I did my PhD at UCL and co-founded Sagaland, an AI gaming platform.

Publications

Selected Papers

rlreasoningoptimizer

Jean Kaddour, arXiv 2026

• What: Group-based RL via distribution matching, yielding a cross-entropy objective.

• Why: Policy gradients can cause updates to overshoot or undershoot.

• Trivia: Independently discovered by Tencent.

TPO matches baselines on easy tasks and outperforms them under sparse reward
agentssafety

Jean Kaddour, Srijan Patel, Gbètondji J-S Dovonon, Leo Richter, Pasquale Minervini, Matt J. Kusner, ICLR 2026 Trustworthy AI

• What: Can agents predict whether they will succeed at a task?

• Why: Overconfident agents are dangerous.

Overconfidence of GPT, Gemini and Claude agents before, after and under adversarial questioning
rlreasoningreward engineering

Zafir Stojanovski, Oliver Stanley, Joe Sharratt, Richard Jones, Abdulhakeem Adefioye, Jean Kaddour†, Andreas Köpf†, NeurIPS 2025 (Spotlight, Top 2%)

• What: 100+ RL envs across 8 domains with configurable complexity.

• Why: Generate virtually infinite training data with adjustable complexity, unlike most previous reasoning datasets, which are typically fixed

• Impact: Used by NVIDIA, FAIR, and Apple.

Example Reasoning Gym tasks from the logic, cognition and games categories
agentsscaffoldsoss

Jean Kaddour et al., Github (5.6k stars)

• What: A Python package with UI for building and debugging agents.

• Why: Debugging long-running agents in a terminal gets cumbersome.

The PySpur visual agent builder
unfathomable datasetshallucinationsmisalignment

Jean Kaddour, Joshua Harris, Maximilian Mozes, Herbie Bradley, Roberta Raileanu, Robert McHardy, arXiv 2023

• What: A review of 16 challenges for LLMs.

• Why: The field is moving fast, hard to keep up with what's worth solving.

The 16 LLM challenges grouped into design, behavior and science
compute-optimal traininghardware awarenessoptimizer

Jean Kaddour∗, Oscar Key∗, Piotr Nawrot, Pasquale Minervini, Matt J. Kusner, NeurIPS 2023

• What: A simple budget-aware LR scheduler outperforms most fancy efficient training methods.

• Why: Every day, there's a new training method; the ones we tried weren't that effective.

• Trivia: We started by trying some ideas that never outperformed our baseline; then realized that our baseline was quite competitive.

BERT training curves: efficient training methods do not beat the budget-aware baseline
optimizer

Jean Kaddour∗, Linqing Liu∗, Ricardo Silva, Matt J. Kusner, NeurIPS 2022

• What: We can find even flatter minima than SAM by adding weight averaging.

• Why: SAM finds flat basins; WA finds flat points inside those basins.

2D loss landscape around the SAM solution with weight averaging

Pretraining

Posttraining

memoryparallelism

Oscar Key∗, Jean Kaddour∗, Pasquale Minervini, NeurIPS 2023 WANT

• What: A method for fine-tuning an arbitrarily large model chunk by chunk (in isolation).

• Why: Allowing the GPU-poor to fine-tune some LLMs too.

• Trivia: Inspired by distributed training techniques, adopted for single-GPU fine-tuning.

Local LoRA loops over dataset and model chunks, keeping only the active LoRA adapters in GPU memory

Evals

ai for sciencereasoning

Long Phan et al. (incl. Jean Kaddour), arXiv 2025

• What: A really hard multiple-choice science benchmark for LLMs.

• Why: Previous benchmarks got hillclimbed quickly but this one will remain the last one standing, promised.

LLM accuracy on HLE compared with GPQA, MATH and MMLU

Aryo Pradipta Gema, Joshua Ong Jun Leang, Giwon Hong, … Jean Kaddour, , NAACL 2025

• What: We expose serious flaws in MMLU and release a smaller and cleaner version, MMLU-Redux.

• Why: MMLU is one of the most popular LLM benchmarks; better benchmarks, better models.

Examples of erroneous instances found in MMLU

Hanchen Wang∗, Jean Kaddour∗, Shengchao Liu∗, Jian Tang, Joan Lasenby, Qi Liu, NeurIPS 2023

• What: A probing suite to profile molecular graph embeddings.

• Why: Downstream-only evaluations can be misleading; better probes yield more faithful assessments.

t-SNE of node centrality in molecular graph embeddings
synthetic datavision modelsspurious correlations

Aengus Lynch∗, Gbètondji J-S Dovonon∗, Jean Kaddour∗, Ricardo Silva, ICLR 2025 SCSL

• What: A vision dataset of cute dogs with spurious correlations between dog breeds and backgrounds.

• Why: Spurious correlations harm the reliability of vision models; previous benchmarks were too easy.

Spawrious dog breeds paired with spuriously correlated backgrounds across train and test environments

Misc

synthetic datavision modelsdiffusion modelsdistillation

Yuwei Yin, Jean Kaddour, Xiang Zhang, Yixin Nie, Zhenguang Liu, Lingpeng Kong, Qi Liu, arXiv 2023

• What: We generate synthetic training data for vision classification models.

• Why: Think of it as knowledge distillation from generative to discriminative models.

• Trivia: This is sort of the training-equivalent of Spawrious.

TTIDA pipeline: text-to-text then text-to-image generation of synthetic training data
causalityspurious correlationscausal rl

Jean Kaddour, Aengus Lynch, Qi Liu, Matt J. Kusner, Ricardo Silva, Foundations and Trends in Optimization, 2022

• What: A survey of how causality can be applied to ML problems.

• Why: Causality allows you to make assumptions about the data-generating process.

Spurious versus causal association between treatment T and outcome Y
data collectionactive learningmeta-learning

Jean Kaddour∗, Steindór Sæmundsson∗, Marc Peter Deisenroth, NeurIPS 2020

• What: We make meta-learning more sample-efficient by letting the model guide the task selection.

• Why: Acquiring datasets can be expensive and slow. Let's make sure we make it worth it.

PAML infers latent task embeddings to choose which task to collect data for next

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