Location
London

Hours
Full Time

Salary
Negotiable

About the Role
At Tripadvisor, the only thing we love more than travel is data. We slice it, we dice it, and we use it to empower our decision making. As a Principal Data Scientist, you will be a leading individual contributor responsible for how experimentation works across the organisation. You will lead through technical depth, setting the standards others work to and raising the quality of measurement and decision-making across the function. You will build the capability that lets teams experiment well without central support: the standards, tooling and protocols that make good practice the default, and a strategy for how it develops over time. Both the speed and the reliability of decision-making should improve as a result.

You will take on the measurement questions we cannot currently answer well, where traffic is thin or the outcomes that matter take months to appear. Your responsibilities include setting the technical standard for experimentation across Product Data Science, from conventional A/B testing to quasi-experimental and Bayesian methods, and making it practical through protocols, frameworks and tooling. You will partner with Product, Engineering and Data Platform teams to improve experimentation velocity without sacrificing rigour.

You will critically assess how experimentation and the decisions that follow affect platform health and growth, making that relationship visible to leadership. You will own the measurement approach for Viator's most complex questions, where standard experimentation is insufficient and the method must be designed rather than selected. You will develop and validate statistical methods, including simulation-based verification, and act as the final technical authority on measurement validity.

Standardising recurring analytical and experimentation processes across the function using automation and AI capabilities will be key, as will designing and landing methodological improvements with organisation-wide impact. You will grow the technical depth of the wider team by reviewing designs, mentoring senior data scientists, and improving how people reason about measurement. Additionally, you will advise on where experimentation is the wrong tool and define alternative approaches.

Experience
Extensive experience in data science or a similar quantitative role, with a proven track record of supporting and influencing a product organisation. Experience with experimentation in two-sided marketplaces, building and validating proxy or surrogate metrics for long-horizon outcomes, Bayesian and hierarchical approaches, and building or improving experimentation platforms or measurement frameworks is highly desirable. Experience in high-scale technology companies, marketplaces, e-commerce, or travel technology organisations is a plus.

About you
Authoritative command of experimentation methods including experimental design, variance reduction, causal inference, bandits, and Bayesian methods, with the ability to develop and validate methodology. Expert proficiency in Python and SQL, deep hands-on experience with statistical modelling, multi-arm bandits, and machine learning techniques such as regression, classification, and clustering. Demonstrated ability to define, implement and operationalise product and feature-level metrics from scratch. Proven ability to improve other teams' experimentation speed and quality through guidance, tooling, and protocols. Strong critical thinking skills with a habit of establishing result trustworthiness before interpretation. Exceptional communication skills to explain measurement, methods, and uncertainty clearly to both technical and non-technical audiences. Ability to build strong cross-functional relationships and drive outcomes without direct authority. Experience applying AI, Large Language Models, agentic AI or automation to improve analytical productivity and decision-making effectiveness. A reputation for raising standards of thinking and decision-making in every team you join.

Qualifications
Bachelor's degree in Statistics, Mathematics, Data Science, Engineering, Physics, Economics, or a related quantitative field.