Senior Data Scientist- Hybrid in London

About Warden AI: AI is being deployed across every industry, transforming how decisions are made and how people interact with technology. But as adoption accelerates, so do concerns about bias, accuracy, and accountability. Warden AI safeguards this transformation by making sure AI systems are fair, transparent, accurate, and explainable.

Founded in 2023 and backed by investors from Playfair, Monzo, Onfido, and Codat, our platform continuously audits AI models, delivering independent oversight through dashboards, reports, and certifications. With teams in London and Austin, we partner with both fast-growing platforms and global enterprises to enable the responsible adoption of AI worldwide.

We are hiring a Senior Data Scientist to define the analytical standards that underpin our evaluation of high-stakes AI systems. The role spans fairness evaluation, rigorous statistical analysis, and an applied understanding of hiring and selection procedures. Most candidates will start strongest in one of these areas and develop depth across all three, enabling you to influence everything from how we design tests and interpret results to how we guide customers, shape product decisions, and meet the expectations of an evolving responsible AI landscape.

You will report to the CTO and work closely with the founders and product team across hands-on analysis, methodological design, and strategic thinking. As one of our early data hires, you will have high agency to shape both how our analytical function evolves and the scope of your own role as we grow.

• Work with our policy experts to translate legal requirements, guidance, and emerging HR and AI standards into clear, defensible audit methodologies.
• Design the foundations for audit execution. Create the datasets, test frameworks, workflows, and analysis patterns that enable consistent, efficient, and high-quality audits.
• Take a long-term, strategic view. Identify emerging risks and opportunities in the industry and the AI landscape, and help define how our AI assurance approach should evolve over the next 12–24 months.
• Guide the evolution of our long-term data capabilities. Anticipate the data assets and analytical foundations we will need as our product expands and the market and industry context evolves.
• Establish the principles, evidence thresholds, and approaches for handling uncertainty and limitations, and help the team communicate findings clearly and consistently.
• Bring technical authority on data, methodology, and context to stakeholder discussions and help address detailed questions with confidence.
• Write accessible explanations of our approach and contribute to white papers, blog articles and industry reports to help build trust in our work.

Relevant academic or equivalent background with a strong, professional senior-level track record over 6+ years and deep expertise in some of the following areas:

• Designing and implementing rigorous evaluation methodologies for responsible AI in production, including black-box and counterfactual approaches, with strong probabilistic reasoning and inference under uncertainty.
• Evaluation data engineering, including designing synthetic and curated test datasets under privacy/PII constraints, grounded in external reference sources, with strong judgement on realism thresholds and the validity limits.
• (Nice to have) HR analytics or I-O psychology, with experience in selection processes, adverse impact analysis, validity considerations, or defensible evaluation practices.
• Fluency in Python for analytical work. You’re comfortable using Python for statistical analysis, data preparation.