10,000 SKUs. One PMax campaign.
No way to tell which were profitable.
Jaycar Electronics is one of Australia’s most recognised electronics retailers — with over 10,000 products spanning everything from hobbyist components to consumer electronics, cables, tools and test equipment.
Their Performance Max campaigns were generating revenue, but the blended ROAS was masking a critical problem: high-margin products weren’t getting enough budget, while low-margin commodity items were eating spend and dragging profitability down.
Google’s machine had no signal about which products were actually profitable. It was optimising for conversion value — not profit. The result: impressive topline numbers, but margins under constant pressure.
PMax treating a $4 cable and a $400 oscilloscope equally. High-value, high-margin products starved of budget.
A 15× ROAS on a 5% margin product is less profitable than a 6× ROAS on a 60% margin product. No system was making this distinction.
Google Merchant Centre had clean data but no performance segmentation. PMax couldn’t distinguish a high-value winner from a budget drain.