Without Context
"The company's revenue grew by 3% over the previous quarter."
→ embedding + BM25
With Prepended Context
This chunk is from ACME Corp's Q2 2023 10-Q filing, in the financial results section.
"The company's revenue grew by 3% over the previous quarter."
→ 50-100 token blurb, then embedding + BM25
Embeddings + BM25
-49%
+ Reranking
-67%
Reduction in top-20 retrieval failure (1 - recall@20)