A better headline.
A weaker underlying trend.
An online shop sees its repeat-purchase rate rise from 24% to 26%. A reassuring result—until the customers are separated by how they were acquired.
What the totals missedRepeat purchasing fell in both groups. The overall rate rose because more customers came from referrals, the group already more likely to return.
That changes the next question: what changed in the experience of each group, and where should the business investigate first?
The headline24% → 26%
Customers who bought again within 90 days +2 pp
Both cohorts have the same 90-day observation window. Figures show repeat buyers out of acquired customers.
This fictional example illustrates a mix effect, not a client result. It identifies a pattern; it does not establish why purchasing changed.