BM25-flavoured but deliberately simpler: a saturating term weight times an IDF.
No document-length normalisation, because answer PDFs vary in length by two
orders of magnitude for reasons that say nothing about relevance, and because a
simpler formula is one fewer thing whose behaviour can drift between versions.
BM25-flavoured but deliberately simpler: a saturating term weight times an IDF. No document-length normalisation, because answer PDFs vary in length by two orders of magnitude for reasons that say nothing about relevance, and because a simpler formula is one fewer thing whose behaviour can drift between versions.