What is a Data Lineage?

When a number on a dashboard looks wrong, lineage is what lets someone trace it backward - through the report, the transformation job, the pipeline, all the way to the original source table or API - instead of guessing where the error was introduced. Without it, debugging a bad metric in a system with dozens of pipelines feeding into a single warehouse table becomes close to impossible. Lineage also matters for compliance: if a regulator or auditor asks where a specific piece of personal data came from and everywhere it has since propagated (for a data subject access request or breach investigation, for example), lineage tracking is what makes that answerable instead of requiring someone to reconstruct it by hand. Modern data platforms increasingly capture lineage automatically by instrumenting pipeline and query engines, rather than relying on documentation that inevitably drifts out of date as pipelines change.