Associate AI/ML Engineer

Optum is a global organization that delivers care, aided by technology to help millions of people live healthier lives. The work you do with our team will directly improve health outcomes by connecting people with the care, pharmacy benefits, data and resources they need to feel their best. Here, you will find a culture guided by inclusion, talented peers, comprehensive benefits and career development opportunities. Come make an impact on the communities we serve as you help us advance health optimization on a global scale. Join us to start Caring. Connecting. Growing together.

This role applies knowledge of experimental methodologies, statistics, optimization, probability theory, and machine learning to build tools and perform statistical analysis, using both general-purpose software and statistical languages. A successful AI/ML engineer must be able to code and develop software that deploys ML models and algorithms in production, while working with large-scale computing frameworks and data analysis systems. Employees in this role should be able to communicate and present complex analytics results and concepts to leadership and internal stakeholders.

Primary Responsibilities:

• Collaborate with cross-functional teams to translate business needs into AI-driven solutions and deploy them in production environments
• Perform end-to-end training and fine-tuning of classical machine learning models, deep learning models, Large
• Language Models (LLMs), including both open-source (e.g., Qwen, LLaMA, Mistral) and closed-source (e.g., OpenAI, Gemini, Anthropic) ecosystems
• Design, train, and optimize semantic and dense vector embeddings for document understanding, search, and retrieval
• Develop semantic retrieval systems with advanced document segmentation and indexing strategies
• Architect and implement GraphRAG pipelines, including knowledge graph representation and retrieval for enhanced contextual grounding
• Scientist Responsibilities: 
  • Collaborate with research, engineering, and product teams to translate cutting-edge AI advancements into production-ready capabilities. Uphold ethical AI principles by embedding fairness, transparency, and accountability throughout the model development lifecycle
• Comply with the terms and conditions of the employment contract, company policies and procedures, and any and all directives (such as, but not limited to, transfer and/or re-assignment to different work locations, change in teams and/or work shifts, policies in regard to flexibility of work benefits and/or work environment, alternative work arrangements, and other decisions that may arise due to the changing business environment). The Company may adopt, vary or rescind these policies and directives in its absolute discretion and without any limitation (implied or otherwise) on its ability to do so

Required Qualifications:

• Master's or Bachelor's degree in computer science, Machine Learning, or related field
• 3+ years of experience in applied AI/ML with statistics, with a aolid track record of delivering production-grade models
• Experience with language modeling - Embedding models, LLM training and fine-tuning (e.g., GPT, LLaMA, Mistral, Qwen)
• Deep expertise in NLP, ensemble techniques, deep learning, transformers, state space-based architecture
• Knowledge of algorithms and techniques within a computational domain with emphasis on text processing 
• Solid in Python programming and working with ML frameworks like pytorch, huggingface transformers, scikit-learn, pandas, numpy etc.
• Solid in SQL/database queries, data preparation, and Exploratory Data Analysis (EDA)
• Working knowledge/experience with cloud ML compute infrastructure - Azure ML and/or AWS

Preferred Qualifications:

• Experience with healthcare data and medical coding systems (e.g., CPT, CM, PCS)
• Prompt optimization framework (AutoPrompt, GreaterPrompt, DSPy)
• Familiarity with regulatory and compliance frameworks in AI deployment

At UnitedHealth Group, our mission is to help people live healthier lives and make the health system work better for everyone. We believe everyone - of every race, gender, sexuality, age, location and income - deserves the opportunity to live their healthiest life. Today, however, there are still far too many barriers to good health which are disproportionately experienced by people of color, historically marginalized groups and those with lower incomes. We are committed to mitigating our impact on the environment and enabling and delivering equitable care that addresses health disparities and improves health outcomes - an enterprise priority reflected in our mission.