Principal Data Scientist

Posted Thursday 22 January 2026 at 01:00 Expires Sunday 8 February 2026 at 00:59

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.

The Role

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.

What You'll Be Doing

• 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

What We're Looking For

• 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

Why Join World of Books?

• 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

Interested?

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.