QA your identity resolution before it merges the wrong people

The checklist for catching bad merges before they poison the warehouse.

1 — Seed test profiles with known-shared and known-distinct emails.
Why: you need ground truth to measure false merges and false splits against.

2 — Pull a sample of merged profiles and eyeball the merge reasons.
Why: shared-device or shared-IP merges are how two real people become one ghost.

3 — Watch the household problem: family members on one device.
Why: probabilistic matching loves to fuse a spouse's behavior into your target.

4 — Alert when any single profile absorbs more than N identifiers.
Why: a profile with 40 emails attached is a merge gone runaway, not a power user.

That's the stack for this week. Forward to a teammate.