Senior Machine Learning Scientist
Salary not listed • UK - London • Full-time
Posted 2d ago
Job Location
UK - London
Tech Stack
Remote Work Policy
On-site
Employment Type
Full-time
Categories
Machine Learning Engineer
About the job
Expedia Group is seeking a Senior Machine Learning Scientist to provide technical leadership within the Search Marketing & Tech organization. This role involves owning end-to-end ML solutions, defining technical roadmaps, and driving complex projects that enhance customer experiences and business performance. The ideal candidate will have a proven track record of delivering high-impact ML projects from concept to production, collaborating closely with engineering teams on multi-quarter initiatives that yield measurable business outcomes. You will contribute to building and optimizing ML models that power metasearch bidding and auction strategies across key partners.
Responsibilities
- Own end-to-end ML solutions within your domain, from problem framing and metric design through data exploration, model development, deployment, and post-launch iteration.
- Define technical direction for your area, including model architecture, system design, data contracts, and integration patterns with existing services.
- Lead multi-quarter ML initiatives in partnership with engineering, product, and business stakeholders, driving projects from ambiguous requirements to production systems at scale.
- Author technical blueprints and system designs that clearly outline objectives, constraints, and trade-offs for complex ML systems.
- Design and implement production-grade ML models (e.g., gradient-boosted trees, deep learning, optimization algorithms, bandits/RL policies) that operate reliably under real-world constraints.
- Build robust training, evaluation, and serving pipelines with embedded observability, drift detection, and failure handling across the ML lifecycle.
- Enhance experimentation and measurement strategies, including A/B tests, causal inference methods, and long-horizon metrics.
- Partner with engineering teams to translate ML designs into scalable, maintainable production systems.
- Influence domain roadmaps by connecting ML opportunities to business objectives, articulating trade-offs, and building stakeholder alignment.
- Translate ambiguous business problems into clear ML formulations with measurable success criteria.
- Lead structured reviews with cross-functional partners, presenting complex technical concepts and trade-offs.
- Raise the technical bar for the broader science community by codifying best practices, experimentation standards, and reusable patterns.
- Mentor other data and machine learning scientists, providing technical guidance.
- Drive adoption of AI best practices.
Requirements
- Master’s or PhD in Computer Science, Statistics, Applied Mathematics, Operations Research, or related quantitative field, or equivalent industry experience.
- 6+ years (Master’s) or 4+ years (PhD) of hands-on experience applying machine learning to real-world problems.
- Demonstrated track record of leading at least one complex, multi-stakeholder production ML initiative that delivered measurable business impact.
- Deep ML expertise in supervised and unsupervised learning, including tree-based methods, generalized linear models, and/or deep learning.
- Strong feature engineering, regularization, calibration, and error analysis skills.
- Strong experimentation and statistics skills: designing and interpreting A/B tests, understanding bias/variance and statistical power, and applying causal inference techniques.
- Fluency in Python and core data/ML libraries (pandas, NumPy, scikit-learn, PyTorch or TensorFlow).
- Solid software engineering practices (clean code, testing, version control, code review).
- Proficient with large-scale data: strong SQL skills and familiarity with distributed data processing (e.g., Spark, Hive).
- Proven ability to lead through influence: aligning cross-functional stakeholders on problem definitions, success metrics, and rollout plans.
- Strong communication skills: articulating technical concepts, trade-offs, and recommendations clearly to both technical and non-technical audiences.
- Experience with complex system diagnosis: combining logs, metrics, experiments, and domain intuition to identify root causes and drive data-informed remediation plans.
- Experience with ads, auctions, marketplace optimization, or bidding systems is preferred.
