Overview
We are seeking a Data Science Contractor specializing in Search and Retrieval to take ownership of the search function for an ongoing project. The successful candidate will work fully remote within the UK and will be responsible for tuning search relevancy, validating search features, and ensuring quality control before deployment. This role involves collaboration with domain experts and requires a strong background in Elasticsearch or OpenSearch.
Responsibilities
- Own the search function end to end, from index design through to relevancy and query latency.
- Validate every search feature against a gold set, measuring nDCG, MRR, and recall@k before and after.
- Tune Elasticsearch or OpenSearch relevancy using analysers, mappings, boosting, and function scoring.
- Evaluate hybrid dense and sparse retrieval against a keyword baseline and select the superior method.
- Run labelling workflows with domain SMEs, ensuring inter-annotator agreement checks.
- Automate retrieval evaluation within CI to ensure relevancy regressions fail the build.
Requirements
- 5+ years of experience with production search systems.
- Proven expertise with Elasticsearch or OpenSearch in production, including experience with analysers, mappings, and scoring functions.
- Demonstrable experience in relevancy tuning, with measurable improvements.
- Experience in retrieval evaluation, including gold sets, nDCG, MRR, and recall@k.
- Proficient with embeddings and at least one vector store in production.
- Strong skills in Python, including tests and CI/CD exposure.
- Eligible for UK security clearance to SC minimum and willing to undergo vetting.