Reddit Engineering Jobs in Ontario (NOW HIRING)

Reddit's Ads Data Science team is looking for a Senior Staff Data Scientist to lead the scientific strategy behind Reddit's ads measurement and signal systems. This role sits at the center of how Reddit proves advertiser value, improves signal quality, builds privacy-aware measurement systems, and connects ads exposure to real advertiser outcomes.

As a Senior Staff Data Scientist for Ads Measurement, you will be the principal architect of our technical vision and the driving force behind the next generation of our measurement ecosystem. In a landscape rapidly shifting due to privacy regulations, browser changes, and evolving platform dynamics, you will spearhead innovation across experimental design (incrementality/lift), identity, signals, and privacy-safe 1P/3P measurement.

This is a high-visibility, high-impact role requiring a rare blend of deep experimentation & causal inference expertise, strategic foresight, and the ability to influence cross-functional executives and industry standards. You will not just adapt to the changing ad-tech environment, you will redefine how we measure value.

• Technical Vision & Strategy: Define the long-term data science vision & strategy across ads measurement, signal quality, identity, attribution, and privacy. Establish how Reddit should evaluate advertiser value, measurement quality, and signal utility across first-party and third-party products.
• Set the Cross-Pillar Measurement Science Strategy: Define the long-term data science strategy across ads measurement, signal quality, identity, attribution, and privacy. Establish how Reddit should evaluate advertiser value, measurement quality, and signal utility across first-party and third-party products.
• Build Trusted Measurement and Evaluation Frameworks: Create rigorous frameworks for validating lift, attribution, identity quality, modeled conversions, signal loss recovery, and privacy-aware measurement. Define ground truth, objective functions, quality metrics, guardrails, and decision frameworks that guide product and engineering investments.
• Advance Experimentation and Causal Inference at Scale: Lead the evolution of Reddit's experimentation and lift methodologies across Brand Lift, Conversion Lift, Split Testing, and emerging measurement products. Improve study quality, reduce bias and contamination, and develop scalable diagnostics for experiment health, feasibility, and interpretability. Partner with Ads Engineering to operationalize complex causal models, ensuring that scientific methodologies are not only accurate but also performant, scalable, and resilient in high-throughput production environments.
• Connect Signals, Identity, and Ranking Outcomes: Quantify how signal quality, match rates, identity resolution, modeled conversions, and privacy changes affect bidding efficiency, CPA, ROAS, and advertiser outcomes. Partner with modeling and ranking teams to translate measurement improvements into performance gains.
• Guide Privacy-Aware Ads Measurement: Lead a privacy-first measurement paradigm, positioning Reddit as a market leader in trusted advertising by recovering signal utility through compliant modeling.
• Create Durable Data Science Infrastructure and Standards: Lead cross-org efforts to define reusable methodologies, dashboards, scorecards, quality metrics, and best practices. Build repeatable systems that improve how Ads DS evaluates launches, monitors regressions, sizes opportunities, and communicates impact.
• Influence Senior Cross-Functional Strategy: Partner with senior leaders across Product, Engineering, Sales, Marketing Science, Legal/Privacy, and Ads leadership to shape roadmap decisions. Translate complex scientific tradeoffs into clear business and product recommendations.
• Uplevel the Data Science Organization: Mentor Staff and Senior data scientists, sponsor high-impact technical work, and raise the bar for causal inference, measurement science, identity evaluation, data quality, and cross-functional decision-making across Ads DS.

• Advanced degree in Statistics, Economics, Mathematics, Computer Science, Operations Research, Physics, or a related quantitative field, or equivalent industry experience.
• 10+ years of industry experience in data science, applied science, economics, statistics, or a related quantitative role.
• Deep expertise in ads measurement, experimentation, causal inference, attribution, marketplace measurement, or ads optimization.
• Proven track record leading ambiguous, cross-functional, multi-pillar problem spaces with measurable business impact.
• Strong command of statistical modeling, experimental design, causal inference, and measurement methodology.
• Experience defining metrics, evaluation frameworks, quality guardrails, and decision systems for complex products.
• Demonstrated ability to balance long-term strategic vision with hands-on execution of complex technical ideas.
• Advanced proficiency in SQL and Python or R. 
• Ability to influence senior product, engineering, and business leaders through clear technical judgment and communication.
• Demonstrated ability to mentor senior ICs and improve technical standards across a data science organization.
• Demonstrated agility in adopting AI tools to amplify your personal output, turning complex methodologies into working prototypes with modern speed and efficiency.

• Experience with ads identity, conversion modeling, signal loss, modeled conversions, match-rate optimization, or identity graph evaluation.
• Experience with lift measurement, brand lift, conversion lift, incrementality testing, MMM, MTA, or third-party measurement partnerships.
• Experience working on privacy-constrained measurement, clean rooms, aggregation, consent-aware systems, or privacy-preserving modeling.
• Experience partnering with ranking, bidding, or machine learning teams to connect measurement quality to optimization outcomes.
• Familiarity with two-sided marketplaces, auction systems, performance advertising, or advertiser-facing measurement products.
• Experience building durable internal frameworks, training programs, scorecards, or methodology standards adopted across an organization.

Benefits:

• Global Benefit programs that fit your lifestyle, from workspace to professional development to caregiving support
• Family Planning Support
• Gender-Affirming Care
• Mental Health & Coaching Benefits
• Comprehensive Medical Benefits & Health Care Spending Account
• Registered Retirement Savings Plan with matching contributions
• Income Replacement Programs
• Flexible Vacation & Paid Volunteer Time Off
• Generous Paid Parental Leave

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