# The Offline-Online Gap: The Dacrema Crisis and Correct Protocol Selection

> Source: https://sukruyusufkaya.com/en/learn/oneri-sistemleri/offline-online-bosluk-dacrema-krizi-protokol
> Updated: 2026-05-13T13:29:34.571Z
> Category: Öneri Sistemleri
> Module: Module 3: Evaluation Protocols
**TLDR:** In 2019, Dacrema, Cremonesi, Jannach paper shook the recommender literature: 'Are neural recommenders really better? Most are beaten by even classic k-NN.' This lesson covers the reproducibility crisis, the offline-online correlation problem, and how to select the correct protocol.