Hello, my name is

Yi Chern Tan.

I am a research scientist / engineer with experience building large language models and post-training. @Cohere, I have launched Command and Aya models, including Command A, Command R+, and Command R.

I have also published on interpretability, fairness, representation learning and semantic parsing at NeurIPS, ICLR, ACL and EMNLP. I was previously @Waymo, @Facebook and @Yale.

Scholar LinkedIn GitHub Resume
About

My research interests lie in building emergent models of intelligence that are helpful, robust and aligned with human values. To pursue this, my current research direction is in post-training large language models that are capable of complex instruction following and agentic behaviour, and which are human-aligned. My prior research also spanned the intersection of language + X ∈ {learning, representation, bias, reasoning} and technology + Y ∈ {ethics, culture, government, security}.

Currently at Cohere, I am the technical lead for post-training recipes. I lead a research team to determine the best post-training recipes and apply them to develop Cohere's flagship large language models that power our agentic AI platform for enterprises. Our Command {A, R7B, R+, R} and Aya models are available as open-weights for the research community.

Apart from research, I also have experience in products and policy. At Waymo, I developed models to determine the true collision rate of self-driving cars in simulation given real and simulated driving episodes, for the purpose of accurate safety benchmarking. At Facebook, I used transformer-based models for the detection of harmful comments on Instagram. At Singapore's Smart Nation and Digital Government Office, I authored strategy papers and analyses on the societal harms of AI and the responsible deployment of human-centered AI systems.

At Yale, I was advised by Dragomir Radev (LILY Lab), Robert Frank (CLAY Lab) and Elisa Celis (Controlling Bias in AI Group). I also worked with John Lafferty to create a curriculum for, and teach, text data science.

Experience
Aug 2022 - present
Post-Training, Generative Modeling
Staff Member of Technical Staff and Technical Lead, Recipes
Mar 2022 - Aug 2022
Simulation
Machine Learning Engineer
May 2019 - Aug 2019
Instagram
Software Engineering Intern
Publications

(see Google Scholar for updated list)

*= equal contribution

GraPPa: Grammar-Augmented Pre-Training for Table Semantic Parsing
Tao Yu, Chien-Sheng Wu, Xi Victoria Lin, Bailin Wang, Yi Chern Tan, Xinyi Yang, Dragomir Radev, Richard Socher, Caiming Xiong
ICLR 2021 (Long Paper)
DART: Open-Domain Structured Data Record to Text Generation
Linyong Nan, Dragomir Radev, Rui Zhang, Amrit Rau, Abhinand Sivaprasad, Chiachun Hsieh, Xiangru Tang, Aadit Vyas, Neha Verma, Pranav Krishna, Yangxiaokang Liu, Nadia Irwanto, Jessica Pan, Faiaz Rahman, Ahmad Zaidi, Mutethia Mutuma, Yasin Tarabar, Ankit Gupta, Tao Yu, Yi Chern Tan, Xi Victoria Lin, Caiming Xiong, Richard Socher, Nazneen Fatema Rajani
NAACL 2021 (Long Paper)
ESPRIT: Explaining Solutions to Physical Reasoning Tasks
Nazneen Fatema Rajani, Rui Zhang, Yi Chern Tan, Stephan Zheng, Jeremy Weiss, Aadit Vyas, Abhijit Gupta, Caiming Xiong, Richard Socher, Dragomir Radev
ACL 2020 (Long Paper)
Assessing Social and Intersectional Biases in Contextualized Word Representations
Yi Chern Tan, L. Elisa Celis
NeurIPS 2019
Spotlight Paper
CoSQL: A Conversational Text-to-SQL Challenge Towards Cross-Domain Natural Language Interfaces to Databases
Tao Yu, Rui Zhang, He Yang Er, Suyi Li, Eric Xue, Bo Pang, Xi Victoria Lin, Yi Chern Tan, Tianze Shi, Zihan Li, Youxuan Jiang, Michihiro Yasunaga, Sungrok Shim, Tao Chen, Alexander Fabbri, Zifan Li, Luyao Chen, Yuwen Zhang, Shreya Dixit, Vincent Zhang, Caiming Xiong, Richard Socher, Walter Lasecki, Dragomir Radev
EMNLP 2019 (Long Paper)
SParC: Cross-Domain Semantic Parsing in Context
Tao Yu, Rui Zhang, Michihiro Yasunaga, Yi Chern Tan, Xi Victoria Lin, Suyi Li, Heyang Er, Irene Li, Bo Pang, Tao Chen, Emily Ji, Shreya Dixit, David Proctor, Sungrok Shim, Jonathan Kraft, Vincent Zhang, Caiming Xiong, Richard Socher and Dragomir Radev
ACL 2019 (Long Paper)
Open Sesame: Getting Inside BERT's Linguistic Knowledge
*Yongjie Lin, *Yi Chern Tan, Robert Frank
ACL 2019 (BlackboxNLP Workshop)
Teaching
YData: Seminar on Text Data Science
Undergraduate Learning Assistant (John Lafferty)
Data Structures and Programming Techniques
Undergraduate Learning Assistant (James Glenn)
Algorithms
Undergraduate Learning Assistant (James Glenn)
Professional Service
Program Committee / Reviewer
NeurIPS 2021 (Outstanding Reviewer Award) - 2025
ICLR 2022 - 2025
ICML 2022 - 2024
COLM 2024 - 2025
EMNLP 2021 - 2022