Senior Data Scientist 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.

About the role

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. Your work will elevate our analytical standards, strengthen the confidence customers place in us, and play a central role in establishing Warden as the standard‑setter for rigorous, defensible evaluations. 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.

What you’ll do

• Set and uphold rigorous analytical methodology.
• Define the statistical tests, fairness metrics, sampling strategies, and evaluation frameworks we rely on, and embed the checks and validation patterns that keep our analytical work accurate, reproducible, and defensible.
• Translate regulations and standards into practical tests.
• Design the foundations for audit execution.
• Take a long‑term, strategic view.
• Guide the evolution of our long‑term data capabilities.
• Define how we analyze and interpret results.
• Support key high‑stakes conversations.
• Contribute to documentation and external credibility.

What you should bring

• Relevant academic or equivalent background with a strong, professional senior‑level track record over 5+ years and deep expertise in at least two of the following areas:
• AI bias and responsible AI, including fairness evaluation, model assessment, or the design of responsible‑AI practices in applied settings.
• HR analytics or I‑O psychology, with experience in selection processes, adverse impact analysis, validity considerations, or defensible evaluation practices.
• Statistically rigorous analytical work in regulated or high‑stakes environments, with fluency in statistical reasoning, demonstrated through defensible, reproducible analysis.
• Fluency in Python for analytical work.
• Grow expertise across domains.
• Comfortable with both depth and ambiguity.
• Thoughtful and rigorous.
• A clear and responsible communicator.
• Collaborative and high‑agency.
• Context‑aware and able to connect dots.
• Motivated by impact.

This role isn’t for you if…

• You prefer narrow, well‑scoped analytical problems.
• You need complete information before acting.
• You don’t enjoy creating structure from ambiguity.
• You’d rather follow established methods.
• You’re uncomfortable owning the quality bar.
• You prefer to stay behind the scenes.
• You avoid work that blends analysis with explanation.
• You prefer to avoid external scrutiny.

What we offer:

• 33 days holiday (incl. bank holidays)
• Hybrid working model (we spend 3 days/week in our London office)
• Learning and Development budget of £500 per year

Interview process

Our interview process involves the following stages:

• Initial screen (40min) - Intro call with our CTO to align on your background and the role.
• Founder screen (40min + 40min) - Conversation with our CEO about values, how you collaborate in a high‑agency, fast‑moving environment, and how you turn expertise into customer and market trust.
• Conversation with our CTO/Data about your analytical judgement, how you identify what really matters in ambiguous, high‑stakes evaluations, and your clarity of communication.
• Take‑home task - Short analytical case study that reflects the kind of real‑world evaluation challenges we face and sets the stage for the on‑site case review.
• On‑site interview (80min) - A collaborative case review and a conversation about the strategic impact you could have on Warden over the next 12–24 months.
• Reference checks & Offer - We move quickly from references to a clear offer.

If you have any specific questions or want to talk through reasonable adjustments ahead of or during the application, please contact us at any point at hiring@warden-ai.com.

Equal opportunities for everyone

Diversity and inclusion are a priority for us, and we are making sure we have lots of support for all of our people to grow at Warden AI. We embrace diversity in all of its forms and create an inclusive environment for all people to do the best work of their lives with us. This is integral to our mission of supporting the responsible adoption of AI systems. We’re an equal‑opportunity employer. All applicants will be considered for employment without attention to ethnicity, religion, sexual orientation, gender identity, family or parental status, national origin, veteran status, neurodiversity status or disability status.