The brand was spending £34k a month across paid search and paid social, and growing. Blended cost per acquisition had drifted from £58 to £67 over two quarters and nobody could say why. Both platforms reported the growth as theirs.
What we found
Retargeting and branded search were claiming conversions from customers who had already bought twice. Once we reconciled platform-reported conversions against the order table, 38% of paid spend was landing on people the business already owned a relationship with.
- Retargeting cost per acquisition was £74 against a first-order margin of £39
- Branded search was cannibalising organic on 61% of clicks
- Lifecycle email was measured last click and looked like a rounding error
What we did
We rebuilt tracking server-side, defined a single conversion reconciled to finance, and ran a four-week geo holdout to price incrementality properly. Retargeting was cut to a maintenance budget. The saving funded a lifecycle programme that had been sitting in a deck for a year.
Where it landed
Blended cost per acquisition settled at £41.20 within two quarters on flat spend. The finding was uncomfortable and the fix was boring, which is usually the shape of it.
They told us in week two that a third of our budget was buying repeat customers at new customer prices. Nobody had said it out loud before.
A pipeline number finance and marketing finally shared
One warehouse, one definition of a qualified lead, and a weekly report nobody had to caveat.