An Empirical Analysis of Retrieval and Evaluation in the RecSys Challenge 2026 Music-CRS Track
We describe a solo entry to the ACM RecSys Challenge 2026 Music-CRS track (team Siwon, CodaBench swlee9087): a frozen, inference-only system that combines BM25, a frozen instruction-tuned text embedder, and a listening-history centroid through Reciprocal Rank Fusion, followed by a two-stage response generator. It reach...