Back to our test from last week:
Take a look at Transitionals. Your matchback results tell you that you generate $1.47 profit. Reality (mail vs. holdout = increment) tells us that we generate $0.29 profit.
51.9% of demand in this segment is generated organically ... meaning that our matchback results are literally doubling the real performance of the segment.
This doesn't cause the business harm when we're talking about productive customers. But when we're talking about segments that spend maybe 70% of this outcome, well, then we are harming the business, we're mailing catalogs we should not be mailing.
This is a classic use of Traditionals, Transitionals, and Transformationals. We overlay the results on our existing mailing strategy, and we quickly learn how we should be mailing customers.