Bidding algorithms inherit your measurement errors
Smart Bidding, Performance Max, and Meta's Advantage campaigns all work the same way: you tell the platform what a conversion is worth, and it finds more people likely to produce one. That makes your conversion definition the most important input in the account — more important than bids, more important than creative.
When the definition is wrong, the failure is not visible as an error. It is visible as a campaign that reports well and produces nothing. We have audited accounts where the primary conversion action was a thank-you pageview that also fired on a newsletter signup, and the algorithm had spent months efficiently buying newsletter signups.
