Job Title

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. #J-18808-Ljbffr