# Data Splitting Strategies: Random, Time, User, Leave-One-Out — Practical Trade-Offs

> Source: https://sukruyusufkaya.com/en/learn/oneri-sistemleri/veri-bolme-stratejileri-random-time-user-loo
> Updated: 2026-05-13T13:29:34.393Z
> Category: Öneri Sistemleri
> Module: Module 3: Evaluation Protocols
**TLDR:** How you split MovieLens changes NDCG — 0.15 or 0.25. This lesson covers 5 main split strategies, when each is correct, when each leaks, and a comparison from a production realism standpoint.