# BM25 Projects at AI Tinkerers

> Canonical HTML: https://aitinkerers.org/technologies/bm25
> Markdown URL: https://aitinkerers.org/technologies/bm25.md
> Technology record last updated: 2026-03-07T18:27:51Z
> Generated: 2026-10-25T12:55:58Z

BM25 (Best Matching 25) is the core keyword-based ranking function used in information retrieval to score a document's relevance to a query, effectively replacing traditional TF-IDF.

BM25 is a robust, decades-old ranking function, developed for the Okapi information retrieval system in the 1980s and 1990s, that remains foundational for modern search engines (e.g., Elasticsearch, Lucene). It calculates a relevance score by combining three factors: Term Frequency (TF), Inverse Document Frequency (IDF), and Document Length Normalization. Critically, it improves upon TF-IDF by incorporating a saturation mechanism for TF, meaning additional term occurrences in a single document contribute diminishing returns to the score. Furthermore, it normalizes scores by document length using the parameter 'b' to prevent overly long documents from unfairly dominating rankings, ensuring accurate, focused results for keyword-based queries.

- Official technology site: https://en.wikipedia.org/wiki/Okapi_BM25
- Public AI Tinkerers demos and talks: 5
- Result page: 1 of 1

## Recent Public Talks and Demos

### [Salve tudo o que puder: buscador local que acha qualquer coisa da minha vida em 25ms](https://curitiba.aitinkerers.org/talks/rsvp_htrQvE_vtiI)

- Event context: AI Tinkerers Curitiba: Encontro de Agosto (no EBANX) — 2026-08-26 — Curitiba
- Public talk page: https://curitiba.aitinkerers.org/talks/rsvp_htrQvE_vtiI

### [Retrieval That Survives a Hostile Web](https://montreal.aitinkerers.org/talks/rsvp_K9jOmd9xYag)

- Event context: AI Tinkerers Montreal - May Demo Meetup @ Ubisoft — 2026-05-26 — Montreal
- Public talk page: https://montreal.aitinkerers.org/talks/rsvp_K9jOmd9xYag

### [Más allá del RAG: Grafos universales para datos no universales](https://santiago.aitinkerers.org/talks/rsvp_Ic5kPKxkc3I)

- Event context: Estructura, Risa y Ecosistemas: el nuevo ADN de la IA Chilena — 2025-10-29 — Santiago
- Public talk page: https://santiago.aitinkerers.org/talks/rsvp_Ic5kPKxkc3I

### [From Guitar Manual to Training Data: Automated Domain-Specific AI Dataset Generation](https://brisbane.aitinkerers.org/talks/rsvp_DOGNvsOOFE0)

- Event context: AI Tinkerers – Brisbane Inaugural Meetup · 11 September 2025 — 2025-09-11 — Brisbane
- Public talk page: https://brisbane.aitinkerers.org/talks/rsvp_DOGNvsOOFE0

### [Covariate Search](https://hong-kong.aitinkerers.org/talks/rsvp_bHTSKW0CfRo)

- Event context: AI Tinkerers - Hong Kong Meetup (December) - Inauguration — 2024-12-19 — Hong Kong
- Public talk page: https://hong-kong.aitinkerers.org/talks/rsvp_bHTSKW0CfRo

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