Machine Learning Scientist III

At Expedia Group, we help travelers explore the world, one journey at a time. As a global travel company powered by passionate people, trusted partnerships, and leading technology, we connect travelers, partners, and advertisers through our consumer brands, B2B network, and travel advertising business.

Here, you'll do meaningful work that helps millions of people discover, book, and experience travel with more ease, confidence, and joy. Our five Behaviors-Traveler First, Think Big, Operate with Excellence, Ownership Mindset, and Succeed Together-help foster a supportive environment where people can grow their careers and have the flexibility, benefits, and support to do their best work. Join us and build for travelers everywhere.

The EG Advertising Machine Learning team sits at the heart of Expedia Group’s global advertising marketplace—a fast-growing, high-impact business at the intersection of travel, technology, and commerce. The team develops the predictive models that power our platform, including click-through rate and booking propensity models, as well as deeper insights into advertiser bidding behaviour and broader marketplace dynamics. It’s a unique environment where machine learning directly shapes real-time auctions, personalised experiences, and large-scale optimisation across a complex two-sided ecosystem.

As a Machine Learning Scientist III, you’ll play a key role within this team, applying machine learning to connect millions of travellers with thousands of partners. One of the most exciting aspects of the role is the end-to-end visibility across both auction and personalisation systems, allowing you to drive meaningful, system-wide impact rather than focusing on a single component. Working closely with product and engineering partners, you’ll combine deep data exploration with strong business context to design and deliver scalable, production-ready solutions that directly influence user experience and marketplace performance.

• Design, develop, and apply machine learning, statistical, and optimization models to solve business problems in EG Advertising, including predictive modelling for ad auction systems (e.g., click-through rate, booking propensity, and advertiser bidding dynamics), improving both partner and traveller outcomes.
• Translate ambiguous business questions into measurable scientific problems, defining success metrics and delivering data-driven recommendations grounded in experimentation, deep data exploration, and marketplace understanding.
• Partner closely with engineers, product managers, analysts, and business stakeholders to product ionize models, influence roadmap decisions, and drive adoption of ML-powered solutions across both partner-facing and traveller-facing systems.
• Build and evaluate scalable approaches across multiple technical domains, including feature engineering, model development, experimentation design (A/B testing), data modelling, and integration into production services within large-scale distributed systems.
• Safely integrate and operate AI/ML-enabled solutions that improve outcomes, including applying modern ML techniques and selective use of GenAI/agentic AI approaches to enhance modelling, experimentation, and system capabilities.
• Contribute strong technical judgment through documentation, code reviews, model monitoring, and operational best practices that support reliable, scalable, and reusable scientific solutions across the advertising marketplace.

• Advanced degree (MS or PhD) in Machine Learning, Computer Science, Statistics, Applied Mathematics, Economics, or a related field.
• 5+ years of relevant industry experience applying machine learning, statistical modelling, experimentation, or…