Field notes · 2026-01-08
When two segments overlap too much
Overlap is normal. The problem is when overlapping groups get different treatments that cancel each other out.
Audience groups rarely form clean circles. A person can be both a high-frequency opener and a low spender. That dual membership is a fact, not a modeling failure.
Trouble starts when the push notification plan treats them as “loyal engagers” while the pricing experiment treats them as “price sensitive,” on the same week, with no shared owner.
In our audits we draw a simple matrix: shared people on one axis, conflicting treatments on the other. If a cell fills quickly, we merge, nest, or assign a primary owner for that period.
Nesting works well for apps with seasonal use. A parent segment “active in term time” can hold child labels for morning and evening openers without inventing a fifth top-level group.
Document the conflict rule in one sentence. Teams forget why a merge happened; the sentence saves the next planning cycle from recreating the same split.