Principal Data Scientist

At World of Books
, we’re on a mission to become the Planet’s Bookstore — helping people read more while wasting less. As a certified B-Corp and a £200m+ global ecommerce business, data science sits at the heart of how we price millions of books sustainably and profitably.

We’re now looking for a Principal Data Scientist to play a critical technical leadership role in shaping how advanced modelling and experimentation are applied to pricing at scale.

This is a senior individual contributor role (no people management), focused on solving complex, high-impact pricing problems through experimentation, causal inference and applied machine learning.

You’ll work closely with our Data Science Manager
, engineers and commercial leaders, acting as a technical authority and mentor while remaining hands-on.

• Leading advanced pricing optimisation, elasticity modelling and experimentation
• Designing and evaluating A/B tests, bandits and quasi-experiments
• Building and deploying production-grade models with strong observability
• Setting practical standards for modelling, experimentation and DS workflows
• Mentoring senior and mid-level data scientists through review and example
• Advising stakeholders on trade-offs between rigour, speed and business value
• Identifying future high-value data science use cases beyond pricing

• Deep experience applying data science in commercial environments (pricing, ecommerce or marketplaces ideal)
• Expert Python and strong SQL
• Advanced knowledge of statistics, ML and causal inference
• Proven experience deploying and iterating on models in production
• Ability to influence through expertise and communicate clearly with senior stakeholders
• Pragmatic, outcome-focused mindset with comfort in ambiguity

• Work on meaningful, planet-positive problems at global scale
• A true Principal IC role with influence but no line management
• Partner closely with an experienced DS Manager who owns strategy and prioritisation
• Help shape how data science is practised in a growing, evolving organisation
• Be part of a mission-driven, collaborative and inclusive culture

If you’re a senior data scientist who thrives on complex problems, hands-on technical leadership and real-world impact — we’d love to hear from you.

World of Books is proud to be an equal opportunities employer and is committed to building a diverse and inclusive team.