The AI Takeover in Paid Search: What PMax and Broad Match Actually Change

Google's AI-powered campaigns are not optional anymore. Performance Max has swept across accounts and now accounts for a substantial share of spend almost by default, while broad match has quietly expanded to capture queries that exact and phrase match used to hold back. The results are often good. The visibility is not.

PMax is a black box by design

Performance Max operates across all of Google's inventory simultaneously — Search, Shopping, Display, YouTube, Discover, Maps — with a single campaign and a single budget. The algorithm decides where to show, who to show, and what to show them. Studies have consistently found PMax cannibalizes traffic from standard campaigns, often taking credit for conversions that would have happened through more controlled campaigns anyway. The targeting is largely inferred, and the auction logic is opaque.

What you actually control — and what you don't

The levers that remain are: asset quality, audience signals (which are suggestions, not targeting), negative keywords at the account level, and brand exclusions. Budget and bidding are effectively surrendered to the algorithm. That's the trade: Google's AI may outperform a human-managed campaign in aggregate ROAS, but you lose the ability to trace which placements, queries, or audiences drove which outcomes. The account becomes harder to diagnose when things go wrong.

The record matters more, not less

When the AI is making decisions you can't directly observe, the settings you can control become the thing worth watching. Asset groups, audience signals, brand exclusions, bidding targets — these are the dials that shape what the algorithm does. If those change without a record, you lose the ability to correlate account behavior with outcomes. An AI-managed account still produces a change history; that history just lives outside the platform's own reporting, in whatever record you keep yourself.