Principal Applied Scientist

Full Job Description

Design, develop, and deploy state-of-the-art machine learning, information retrieval, large language model, and agentic AI solutions that improve the quality, understanding, and usefulness of web-scale content and knowledge systems. Drive scientific strategy and technical direction for large-scale machine learning and AI initiatives across Web Data Platform. Lead end-to-end development of scientific solutions, including problem formulation, experimentation, model development, evaluation, production deployment, and long-term measurement of impact. Define long-term technical roadmaps, influence organizational investments, and identify new opportunities where advances in AI can create meaningful customer value. Establish rigorous experimentation frameworks, evaluation methodologies, and success metrics to drive scientific excellence and measurable product impact. Develop novel approaches for content understanding, quality estimation, risk detection, trust modeling, and ecosystem health measurement at Web scale. Mentor and grow other scientists, raise the scientific bar across the organization, and contribute to recruiting and cultivating world-class talent. Drive cross-organizational collaboration and influence across teams, helping shape technical strategy beyond your immediate area of ownership. Bachelor's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 6+ years related experience (e.g., statistics, predictive analytics, research) OR Master's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 4+ years related experience (e.g., statistics, predictive analytics, research) OR Doctorate in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 3+ years related experience (e.g., statistics, predictive analytics, research) Master's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 9+ years related experience (e.g., statistics, predictive analytics, research) OR Doctorate in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 6+ years related experience (e.g., statistics, predictive analytics, research) OR equivalent experience. Proven track record of shipping machine learning or AI capabilities that operate at internet scale and directly impact product quality, customer satisfaction, or business outcomes. Experience developing ranking, retrieval, classification, quality, trust, safety, spam, abuse, content understanding, or recommendation systems. Hands-on experience with modern AI systems including foundation models, LLMs, SLMs, agents, tool use, evaluation frameworks, and prompt engineering. Experience with distributed data processing and model training using large-scale compute platforms. Experience applying Responsible AI, model governance, experimentation, and online measurement methodologies. Solid software engineering skills in Python, C++, C#, Java, or similar languages. Experience leading cross-organizational technical initiatives and influencing engineering and product direction without direct authority. Publications, patents, or recognized technical contributions in machine learning, information retrieval, search, NLP, GenAI, or related fields. Demonstrated experience mentoring senior scientists and raising scientific rigor across an organization.