Chen Bo Calvin Zhang

I am currently the ML Research Ops Lead at Scale AI, where I work on evaluations, benchmarks and leaderboards.

Before joining Scale AI, I was a research intern at CHAI, where I worked with Micah Carroll on red teaming large language models. I also spent time as a visiting scholar at MIT, where I focused on online learning and reward design for reinforcement learning. During that time, I was fortunate to collaborate with Zhang-Wei Hong, Aldo Pacchiano, and Pulkit Agrawal.

I hold an MSc in Data Science from ETH Zurich, where I worked with Giorgia Ramponi on preference-based reinforcement learning.

Earlier, I completed my BSc (Hons) in Computer Science and Mathematics at the University of Manchester, where I researched adversarial attacks in deep reinforcement learning under the supervision of Tingting Mu.

I am interested in sequential decision making and AI safety and alignment.

Google Scholar / Twitter / GitHub / LinkedIn

News

Jun 19, 2025	Excited to share our new paper SHADE-Arena, in collaboration with Anthropic!
Jan 27, 2025	I am excited to join Scale AI as a ML Research Ops Lead!

Latest Posts

Sep 16, 2024	The Quantum Cheese Conundrum

Selected Publications

ICLR

ORSO: Accelerating Reward Design via Online Reward Selection and Policy Optimization

Chen Bo Calvin Zhang, Zhang-Wei Hong, Aldo Pacchiano, and Pulkit Agrawal

In The Thirteenth International Conference on Learning Representations, 2025

Bib HTML

@inproceedings{zhang2025orso,
  title = {ORSO: Accelerating Reward Design via Online Reward Selection and Policy Optimization},
  author = {Zhang, Chen Bo Calvin and Hong, Zhang-Wei and Pacchiano, Aldo and Agrawal, Pulkit},
  booktitle = {The Thirteenth International Conference on Learning Representations},
  year = {2025},
}

arXiv

Humanity’s Last Exam

Long Phan, Alice Gatti, Ziwen Han, Nathaniel Li, Josephina Hu, Hugh Zhang, Chen Bo Calvin Zhang, Mohamed Shaaban, John Ling, and 2 more authors

arXiv preprint arXiv:2501.14249, 2025

Bib HTML

@article{phan2025humanity,
  title = {Humanity's Last Exam},
  author = {Phan, Long and Gatti, Alice and Han, Ziwen and Li, Nathaniel and Hu, Josephina and Zhang, Hugh and Zhang, Chen Bo Calvin and Shaaban, Mohamed and Ling, John and Shi, Sean and others},
  journal = {arXiv preprint arXiv:2501.14249},
  year = {2025},
}

Preprint

SHADE-Arena: Evaluating Sabotage and Monitoring in LLM Agents

Jonathan Kutasov, Yuqi Sun, Paul Colognese, Teun Weij, Linda Petrini, Chen Bo Calvin Zhang, John Hughes, Xiang Deng, Henry Sleight, and 3 more authors

2025

Bib HTML

@preprint{kutasovshade,
  title = {SHADE-Arena: Evaluating Sabotage and Monitoring in LLM Agents},
  author = {Kutasov, Jonathan and Sun, Yuqi and Colognese, Paul and van der Weij, Teun and Petrini, Linda and Zhang, Chen Bo Calvin and Hughes, John and Deng, Xiang and Sleight, Henry and Tracy, Tyler and Shlegeris, Buck and Benton, Joe},
  year = {2025},
}

ICML

HIP-RL: Hallucinated Inputs for Preference-based Reinforcement Learning in Continuous Domains

Chen Bo Calvin Zhang, and Giorgia Ramponi

In ICML 2023 Workshop: The Many Facets of Preference-Based Learning, 2023

Bib

@inproceedings{zhang2023hip,
  title = {HIP-RL: Hallucinated Inputs for Preference-based Reinforcement Learning in Continuous Domains},
  author = {Zhang, Chen Bo Calvin and Ramponi, Giorgia},
  booktitle = {ICML 2023 Workshop: The Many Facets of Preference-Based Learning},
  year = {2023},
}