Fewer campaigns is the least popular thing I say on a first call. Everyone would rather hear it was the creative, or the bid, or iOS.
So we pull one column. Optimisation events, per campaign, per week.
In this US account, half the campaigns had never cleared 50 in a week. Those four produced 70 events between them. One campaign’s worth of signal, spread across four.
8 US campaign-months, Adjust cohort ROAS at day 28, April to June 2026. Under 50 events a week: 4 of 8 campaigns, $16,843, 23% of budget, 54% ROAS. 50 events a week or more: 4 of 8 campaigns, $58,012, 77% of budget, 80% ROAS. The four under-50 campaigns all launched mid-May, so age and signal move together; holding the month constant, the split is 75% against 54%, so the gap survives after controlling for launch age.
Nobody sets out to do that. It happens one launch at a time. A campaign for the new platform. A campaign for the test. A campaign for the team, because the last one got messy and starting fresh felt cleaner.
None of it looks like a mistake while you are doing it. Fewer campaigns, same budget, everything clears the line.