Data Scientist (Senior Lead)

Experience: 15 to 20+ years

Function: AI & Machine Learning

Location: Cognizant India (Hybrid)

ROLE SUMMARY

Owns the ML and GenAI model strategy for the product. Leads RAG design, hybrid retrieval, model evaluation with LLM-as-a-Judge, and LLM fine-tuning programmes. Sets the standard for how agents retrieve, reason, and generate reliable outputs.

KEY RESPONSIBILITIES
Define and own the ML/GenAI model strategy for all agentic use cases on the platform
Lead RAG pipeline design, hybrid retrieval strategy, and vector/graph database selection
Establish model evaluation frameworks: benchmarking, accuracy, LLM-as-a-Judge calibration
Lead fine-tuning programmes: LoRA, QLoRA, PEFT, DPO, SFT, RFT (Reinforcement Fine-Tuning)
Guide the ML Engineer on MLOps practices, model promotion, and serving optimisation
Run structured A/B tests, model comparisons, and prompt strategy evaluations
Produce model cards, evaluation reports, and executive-level performance insights

TECHNICAL SKILLS
Languages & Libraries: Python; PyTorch,



TensorFlow, scikit-learn, Hugging Face Transformers, LlamaIndex
LLMs & Fine-Tuning: LoRA, QLoRA, PEFT, RFT, RLHF, DPO, SFT, instruction tuning
RAG & Hybrid Retrieval: BM25 + dense vector, reranking (Cohere Rerank, ColBERT, cross-encoders)
Vector & Graph Databases: Pinecone, pgvector, Weaviate, Qdrant; Neo4j, Memgraph
Evaluation: Ragas, DeepEval, HELM, PromptFoo, TruLens; LLM-as-a-Judge design and calibration
MLOps: MLflow, Weights & Biases, experiment tracking, model registry, drift monitoring
Cloud AI: AWS SageMaker, Azure ML, GCP Vertex AI
Statistics: experiment design, A/B testing, causal inference, significance testing

NICE TO HAVE
Published research at NeurIPS, ICML, ACL, or equivalent
Agentic AI framework experience (LangGraph, AutoGen)
Responsible AI tooling: Fairlearn, AI Fairness 360, Giskard
Knowledge graph and LLM knowledge pipeline design experience

📌 Data Scientist Senior Lead Telangana
🏢 Cognizant
📍 Telangana