Machine Learning Scientist - Open Source Lead

LMArena; San Francisco (CA); On-site; USD 130,000 - 170,000; Full time

Benefits offered by this job

Competitive compensation

Comprehensive health and wellness benefits

Opportunity to work on cutting-edge AI

Culture valuing transparency and community impact

Job summary

A pioneering AI evaluation platform in San Francisco is looking for a Machine Learning Scientist to lead open-source research. You will design experiments to evaluate AI models, develop new methodologies, and analyze human interaction data. The ideal candidate has a PhD in a relevant field and strong expertise in machine learning and programming. This role offers competitive compensation, comprehensive benefits, and the chance to work on cutting-edge AI projects in an inclusive and transparent environment.

Qualifications

• PhD or equivalent research experience in Machine Learning, NLP, or a related field.
• Strong understanding of LLMs and deep learning architectures.
• Experience publishing research in ML or NLP.

Responsibilities

• Design and conduct experiments to evaluate AI model behavior.
• Develop metrics, methodologies, and evaluation protocols.
• Analyze large-scale human voting and interaction data.

Skills

Machine Learning

Natural Language Processing

Statistics

Python

Open Science

Education

PhD or equivalent research experience

Tools

PyTorch

JAX

TensorFlow

Job description

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About LMArena

LMArena is the open platform for evaluating how AI models perform in the real world. Created by researchers from UC Berkeley’s SkyLab, our mission is to measure and advance the frontier of AI for real-world use. Millions of people use LMArena each month to explore how frontier systems perform—and we use our community’s feedback to build transparent, rigorous, and human-centered model evaluations. Leading enterprises and AI labs rely on our evaluations to understand real-world reliability, alignment, and impact. Our leaderboards are the gold standard for AI performance—trusted by leaders across the AI community and shaping the global conversation on model reliability and progress. We’re a team of researchers, engineers, academics, and builders from places like UC Berkeley, Google, Stanford, DeepMind, and Discord. We seek truth, move fast, and value craftsmanship, curiosity, and impact over hierarchy. We’re building a company where thoughtful, curious people from all backgrounds can do their best work. Everyone on our team is a deep expert in their field—our office radiates excellence, energy, and focus.

About The Role

LMArena is looking for a Machine Learning Scientist to lead our open‑source research, including open data set and code releases, advancing how the world evaluates and understands AI models in the open. You’ll design, run, and share new methods and experiments that reveal what makes models useful, trustworthy, and capable, grounded in human preference signals and released openly for the full ecosystem and research community to build upon. In this role, you’ll be responsible for taking our commitment to openness from principle to practice, curating high‑impact datasets, developing new methodology and reproducible benchmarks, and releasing code that enables the research ecosystem to push AI evaluations forward. Your work will shape the public leaderboard, power community tools, and strengthen transparency in AI evaluation worldwide. This role is deeply interdisciplinary, working with engineers, product teams, marketing, and the broader research community to advance how we compare models, analyze preference data, and understand factors like style, reasoning, and robustness. You’ll work closely with GTM teams as our spokesperson when it comes to outreach for our open research efforts: strengthening research partnerships, expanding research community participation, and championing programs that grow and support our research network.

You’ll

• Design and conduct experiments to evaluate AI model behavior across reasoning, style, robustness, and user preference dimensions
• Develop new metrics, methodologies, and evaluation protocols that go beyond traditional benchmarks
• Analyze large‑scale human voting and interaction data to uncover insights into model performance and user preferences
• Communicate results with the broader research community via academic papers, educational content, conference talks
• Collaborate with engineers to implement and scale research findings into production systems
• Prototype and test research ideas rapidly, balancing rigor with iteration speed
• Partner with model providers to shape evaluation questions and support responsible model testing
• Contribute to the scientific integrity and transparency of the LMArena leaderboard and tools

You’ll have

• PhD or equivalent research experience in Machine Learning, Natural Language Processing, Statistics, or a related field
• Uses personal and professional platforms to amplify open research initiatives and invite collaboration
• Strong understanding of LLMs and modern deep learning architectures (e.g., Transformers, diffusion models, reinforcement learning with human feedback); proficiency in Python and ML research libraries such as PyTorch, JAX, or TensorFlow
• Demonstrated ability to design and analyze experiments with statistical rigor
• Experience publishing research or working on open‑source projects in ML, NLP, or AI evaluation
• Comfortable working with real‑world usage data and designing metrics beyond standard benchmarks
• Ability to translate research questions into practical systems and collaborate across engineering and product teams
• Passion for open science, reproducibility, and community‑driven research

Bonus skills for this role

• Skilled at public speaking, writing, and presenting research work to diverse audiences
• Actively participates in conferences, panels, and online forums to foster relationships and thought leadership
• Builds trust through transparent communication and consistent community engagementServes as a go‑to contact for external researchers, journalists, and partners

What we offer

• We offer competitive compensation and equity aligned to the markets where our team members are based. The base salary range will depend on the candidate’s permanent work location
• Comprehensive health and wellness benefits, including medical, dental, vision, and additional support programs
• The opportunity to work on cutting‑edge AI with a small, mission‑driven team
• A culture that values transparency, trust, and community impact

LMArena provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, color, religion, sex, national origin, age, disability, genetics, sexual orientation, gender identity, or gender expression. We are committed to a diverse and inclusive workforce and welcome people from all backgrounds, experiences, perspectives, and abilities.

Seniority Level

Mid‑Senior level

Employment Type

Full‑time

Job Function

Other

Industries

Research Services