Principal Data Scientist
Marshmallow
full-time
Posted on:
Location Type: Hybrid
Location: London • United Kingdom
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Job Level
About the role
- Provide technical leadership for data science across Claims Fraud, shaping the approach to risk decisioning and fraud detection in partnership with Product and Engineering.
- Design, build and iterate on production ML and Generative AI/LLM systems that support claims validation and automation.
- Collaborate closely with other Claims data scientists to bring system-level thinking to how models, data and workflows fit together, identifying architectural improvements needed to scale decisioning and reduce time-to-production.
- Be vocal about the platform and tooling investments needed (monitoring, feedback loops, QA) to achieve AI-driven end to end claims automation.
- Advocate for robust, scalable, and strategically aligned technical solutions in cross-functional discussions, ensuring current systems and infrastructure contribute to the multi-year vision for automated claims handling.
- Set a high bar for statistical rigour, experimentation and measurement, helping improve how Claims performance and uncertainty are understood and communicated to senior stakeholders.
Requirements
- Significant commercial experience delivering end-to-end Machine Learning solutions, from problem framing and experimentation through to production deployment and ongoing monitoring.
- Hands-on experience building and shipping Generative AI systems in production (not just prototypes), including evaluation, safety/quality considerations, and integration into customer or operational workflows.
- Strong statistical and modelling foundation, with experience in risk-based decisioning under uncertainty (e.g., fraud, credit, insurance, or other regulated domains).
- Proven ability to influence technical direction across Data Science and Engineering, including shaping scalable model/service integration patterns and challenging proposals to drive robust, long-term solutions.
- Strong stakeholder management skills, with confidence communicating trade-offs and pushing back constructively with Product and Engineering to ensure high-quality outcomes.
Benefits
- Flexible working: Spend three days a week with your team in our collaborative London office, and own your own working hours.
- Competitive bonus scheme - designed to reward and recognise high performance.
- Flexible benefits budget - £50 per month to spend on a Ben Mastercard meaning you get your own benefits budget to spend on things you want.
- Mental wellbeing support – Access therapy and mental health sessions through Oliva.
- Learning and development – Personal budgets for books and training courses to help you grow in your role. Plus 2 days a year - on us! - to further your skillset.
- Private health care - Enjoy all the benefits Vitality has to offer, including reduced gym memberships and discounts on smartwatches.
- Medical cash plan - To help you with the costs of dental, optical and physio (plus more!)
- Tech scheme - Get the latest tech for less.
- 33 days holiday (including bank holidays).
- Pension.
- Cycle to work scheme.
- Monthly team socials and company-wide socials every month!
Applicant Tracking System Keywords
Tip: use these terms in your resume and cover letter to boost ATS matches.
Hard Skills & Tools
Machine LearningGenerative AILLM systemsstatistical analysisrisk-based decisioningproduction deploymentdata modelingexperimentationmonitoringautomation
Soft Skills
technical leadershipstakeholder managementcommunicationcollaborationinfluenceproblem framingconstructive feedbackstrategic alignmentcritical thinkingcross-functional collaboration