Staff Data Scientist

Company: Marshmallow
Apply for the Staff Data Scientist
Location: London
Job Description:

Overview

In this role, you provide technical leadership for data science within Claims, shaping risk decisioning and fraud detection. You will design and deploy production ML and Generative AI/LLM systems to support claims validation and automation. You’ll work with Claims data scientists and cross-functional partners to scale decisioning, ensure robust monitoring and governance, and drive measurable automation impact. This is an opportunity to influence platform choices and deliver high-quality, end-to-end AI-enabled solutions that improve the customer journey.

Pay / Benefits

  • Flexible working in London office 3 days a week
  • Competitive bonus scheme
  • Flexible benefits budget (Ben Mastercard)
  • Mental wellbeing support via Oliva
  • Learning and development budgets plus 2 extra days per year
  • Private health care and Vitality benefits

Responsibilities

  • Provide technical leadership across Claims Fraud and risk decisioning with Product and Engineering
  • Design, build and iterate production ML and Generative AI/LLM systems for claims validation and automation
  • Collaborate with Claims data scientists to align models, data, and workflows for scalable decisioning
  • Advocate for platform and tooling investments (monitoring, QA, feedback loops) to enable AI-driven end-to-end automation
  • Influence technical direction to align with multi-year automation vision for claims handling
  • Set high bar for statistical rigour, experimentation, and measurement for senior stakeholders

Key requirements

  • Significant commercial experience delivering end-to-end ML solutions from problem framing to deployment and monitoring
  • Hands-on experience building and shipping Generative AI systems in production with evaluation and integration into workflows
  • Strong statistical foundation with experience in risk-based decisioning under uncertainty (fraud/credit/regulated domains)
  • Proven ability to influence technical direction across Data Science and Engineering
  • Strong stakeholder management and ability to push back constructively with Product and Engineering
  • strong communication and influencing skills
  • ability to challenge assumptions and think systemically
  • resilience in ambiguity and change
  • End-to-end ML in production
  • Generative AI systems/LLMs in production
  • risk-based decisioning and uncertainty handling

Posted: September 14th, 2026