Machine Learning Scientist II

Machine Learning Scientists II

Within the AI & Data organization, the Marketplace Science team develops, optimizes and operationalizes applied science driven marketplace levers that support a healthy, trusted marketplace. The Marketplace Health team builds systems that detect behaviors indicating trust, safety, and marketplace-health risk before they result in larger issues. This work helps protect traveler trust and supports a reliable experience across Expedia Group's marketplace.

Key Responsibilities

In this role, you will:

• Own machine learning projects end to end, from understanding the business need and defining the approach through execution, launch, measurement, and iteration.
• Develop and improve the Marketplace Health Model system to identify behaviors associated with trust, safety, and marketplace-health risks.
• Translate complex marketplace challenges into scalable machine learning and statistical modeling solutions.
• Partner closely with product, engineering, operations, trust and safety, and other stakeholders to understand needs and deliver practical solutions.
• Stay highly engaged with business outcomes by identifying opportunities where machine learning can create meaningful, measurable impact.
• Proactively evaluate opportunities based on potential return on investment, customer impact, risk reduction, and implementation feasibility.
• Design experiments and analyses to assess model performance, business outcomes, and marketplace-health improvements.
• Monitor deployed models and recommend enhancements to maintain quality, reliability, and relevance as marketplace behavior evolves.
• Communicate technical findings, recommendations, trade-offs, and project progress clearly to both technical and non-technical audiences.
• Identify gaps, resolve blockers, and advance projects independently while keeping stakeholders aligned.

Experience and Qualifications:

• Graduate degree in a quantitative field (such as Computer Science, Statistics, Machine Learning, Operations Research, or similar) with focused coursework or research in ML, optimization, or statistical modeling
• Experience developing, evaluating, and applying machine learning models to complex business or product problems.
• Experience designing, developing, and deploying solutions using large language models (LLMs).
• Experience with Python, SQL, and common machine learning libraries and frameworks.
• Experience translating ambiguous problems into measurable objectives, analytical approaches, and actionable recommendations.
• Experience collaborating with cross-functional stakeholders to deliver machine learning solutions from concept through production.
• Proficient communication skills, with the ability to explain technical concepts and business implications clearly.
• Demonstrated ability to work both collaboratively and autonomously, take initiative, and maintain ownership of deliverables.

Preferred Qualifications

• Graduate degree in Deep Learning, NLP, Transformer, LLM
• Experience developing agentic applications or LLM-powered agents.
• Experience with trust and safety, fraud detection, risk modeling, anomaly detection, behavioral modeling, or marketplace optimization.
• Experience working with large-scale, imperfect, or evolving datasets.
• Experience with model monitoring, experimentation, and production machine learning systems.
• Experience balancing customer trust, business value, operational considerations, and model performance.