When two dashboards disagree, “Where did this number come from?” should be answerable without a week of detective work. Data lineage is the record of that journey, from original system through transformations to the report people use.
Trace a single metric first
Take net revenue. Note the source transactions, refund treatment, currency conversion, joins, filters and calculation in the final dashboard. Include the timing: a late refund may change last month’s figure. Capture the person or team responsible for each transformation.
Technical lineage can show that table A feeds table B. Business lineage adds the meaning: why cancelled orders are excluded, when a transaction is considered final and which report is authoritative. Both matter. Automated discovery helps, but it cannot infer every business decision hidden in a spreadsheet or a meeting note.
Use lineage for change management
Before altering a source field, inspect the downstream reports and models it feeds. Before accepting a dashboard figure, inspect its freshness and known exceptions. A visible dependency map can stop an innocent source change from breaking executive reporting.
Keep the map alive
Start with critical data products rather than trying to document every column. Store definitions close to the transformation code and update them during normal releases. Ask analysts to report broken links and unclear terms. Lineage earns its keep when an incident or audit question is resolved faster because the path was already documented.
