Information Retrieval
Definition
Information retrieval deals with finding relevant information in large collections for a specific query.
Search systems index documents and rank hits by relevance. Lexical, semantic, and hybrid methods differ in which signals they use.
Simply explained
How to find not just any book but the most relevant passages to a question in a very large library.
Why it matters in practice
Central for enterprise search, RAG, document research, and knowledge systems.
Example from business
A service portal searches manuals by error code, component, and natural language problem description.
Limits and pitfalls
- Confusing retrieval with factual accuracy; not effectively enforcing permissions before sharing with users or models; choosing filter mode without checking recall and safety; considering only top-1 hits; evaluating without real search queries.
Origin & history
Information retrieval is an independent research field long before modern LLMs. Classic search engines work with indexing, retrieval, and ranking.
Use in mid-sized companies
- Possible applications: document search, RAG, product search, support knowledge, and internal research.
Frequently asked questions
Is IR the same as database querying?
Not necessarily; IR typically optimizes relevance for unstructured or semi-structured information. Is vector search IR? It can be part of an IR system.
Sources
- Raghavan & Schütze, Introduction to Information Retrieval · Manning, Raghavan & Schütze, Introduction to Information Retrieval
- Filtermodi · Microsoft, Filtermodi
Sources checked on 10./11.10.2026.
Editorially reviewed on: