# All quality checks at the end is a common mistake

Canonical URL: <https://datadriven.io/problems/all-quality-checks-at-the-end-is-a-common-mistake-by-the-ti-d0b2d2ae>

Domain: Pipeline Design · Difficulty: medium

## Problem

All quality checks at the end is a common mistake. By the time a problem shows up in the serving layer, several intermediate transforms have already run on bad data, and the diagnostic cost climbs because the failure has to be traced back through every transform between source and gate. The section's rule is checks at every layer boundary so failures stay scoped to the layer where they originated. Place the gates by adding three quality-check nodes on this three-layer pipeline, one between source and raw, one between raw and curated, one between curated and serving, each named with what it asserts at that boundary.

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