What documentation should exist for segmentation rules?

Every segment should have documentation that answers: what is this segment, why does it exist, how is it defined, and who owns it.

Include the segment name and description explaining its purpose in plain language. A developer or new team member should understand the intent without deciphering technical criteria.

Document the exact criteria and logic. List each rule, threshold, and condition. If the segment uses complex boolean logic, write it out explicitly. Include any data sources or fields the segment depends on.

Record dependencies and usage. Which campaigns, automations, or reports reference this segment? If the segment changes or breaks, what downstream effects occur?

Track change history. When was the segment created? Who modified it and when? What were previous criteria before updates? Version history prevents confusion and enables rollback if needed.

Assign an owner responsible for segment accuracy and maintenance. Without clear ownership, segments drift, break, or become orphaned.

Store documentation in a shared location like Notion, Confluence, or a team wiki. Keep it updated as segments evolve.

The captain's log records every course correction. Without it, the next voyage starts blind.