Closing the Long-Short View Gap in Sequential Recommendation Without Cached History

_reachsumit · x · 2026-09-09

A CIKM 2026 paper (Lingfeng Shi et al.) tackles the long-short view gap in sequential recommenders: models trained on long user histories degrade sharply when serving only recent behaviors due to real-time efficiency limits, and prior history-compression approaches add infrastructure overhead and fail in cold-start scenarios.

The authors identify structural flaws rooted in embedding geometry and dataset sparsity, then propose a two-stage framework: replacing dot-product scoring with angular similarity plus a modified softmax to counter prefix position bias, followed by fine-tuning only universal bias and LayerNorm components. Experiments across two backbones and three public datasets show the gap can be closed without caching per-user history states — a lightweight deployment path for practitioners.

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