Principal Data Scientist, Ads

Details

Reddit is a community of communities built on shared interests, passion, and trust and is home to the most open and authentic conversations on the internet. Every day, Reddit users submit, vote, and comment on the topics they care most about. With 100,000+ active communities and approximately 101M+ daily active unique visitors, Reddit is one of the internet’s largest sources of information.

The Ads Data Science team at Reddit is seeking a highly motivated Principal Data Scientist to drive the strategic application of advanced quantitative methods across our advertising platform. In this leadership role you will define and implement foundational data science solutions using statistics, econometrics, machine learning, and other quantitative techniques to optimize Reddit's Ads marketplace. You will partner with Analytics Engineering, Product, Engineering, and Business leaders to set the long-term vision for measurement, prediction, and optimization and mentor the broader team.

Responsibilities

• Define the long-term design and evolution of core Ads Data Science solutions and infrastructure to support scale, revenue growth, and relevance.
• Lead the scientific roadmap and identify gaps/opportunities across platform, auction, targeting, and full-funnel relevance models.
• Take end-to-end ownership of complex domains such as full-funnel acceleration, advertiser lifetime value (LTV), and development of advanced predictive and causal frameworks.
• Define and codify best practices for large-scale statistical modeling, economic analysis, causal inference, offline model evaluation, and A/B experimentation.
• Serve as the domain authority for data scientists, engineers, and product managers on problems involving large-scale behavioral data, foundational models for strategic insights, and marketplace economics.
• Influence the design and definition of core business and performance metrics and collaborate with cross-functional teams to translate ambiguity into measurable outcomes.
• Mentor and lead technically minded peers and senior data scientists, influencing technical and statistical direction across product and engineering organizations.

Requirements

• Demonstrated expertise in at least one of: ads marketplace understanding, auctioning/bidding systems, ads creative & format evaluation, or measurement & experimentation at scale.
• Master's or Ph.D. in Economics, Statistics, Computer Science, Operations Research, or a related quantitative discipline.
  • For M.S. holders: 12+ years of industry experience in applied science, data science, or machine learning engineering roles.
  • For Ph.D. holders: 8+ years of relevant experience in applied science, data science, or machine learning engineering roles.
• Advanced proficiency in statistical programming (Python or R) and SQL.
• Experience with statistical analysis, economic modeling, foundational machine learning, and/or optimization techniques.
• Strong understanding of experimental design, causal inference, and A/B testing methodologies.
• Exceptional problem-solving and communication skills with a track record of influencing product and engineering partners.
• Experience working in fast-paced, ambiguous environments with cross-functional teams.
• Proven experience influencing large organizations (500+ engineers/data scientists) on technical direction, statistical rigor, and machine learning best practices.

Benefits

• Comprehensive healthcare benefits and income replacement programs
• 401(k) match
• Family planning support and gender-affirming care
• Mental health & coaching benefits
• Flexible vacation & Reddit Global Days off
• Generous paid parental leave
• Paid volunteer time off

Pay Transparency

• Base pay range for this position: $26,800 - $365,100 USD
• Role may also be eligible for equity (RSUs) and, depending on position, commission

Additional Notes

• Interviews in select roles/locations may be recorded, transcribed, and summarized by AI (candidates can opt out).
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