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Paid · 2 min read2 July 2026

Google Just Cracked Open the Performance Max Black Box. Use the Diagnostics.

Google's new Performance Max channel report now includes a diagnostics column showing which channels your budget ran on and flagging where performance is being dragged down. The black box finally has a dashboard.

You cannot steer what you cannot see. Google just turned on a light inside the box.

2 min read

Performance Max has always asked you to trust it. Google is finally showing more of its working. The channel performance report, now rolling out with a diagnostics column, tells you which channels your budget actually ran on and flags where something is going wrong.

The report breaks a PMax campaign down across Search, YouTube, Display, Discover, Gmail, Maps and Search partners, with a channel distribution table you can download and a cost toggle that shows spend per channel. The diagnostics sit in a status column. Hover over it and Google surfaces potential issues on a specific channel plus guidance on how to fix them. It is the closest the black box has come to a dashboard.

This matters because the loudest complaint about Performance Max has always been the same. You hand over the budget and get a result with no idea where the money went. Channel-level reporting and diagnostics start to answer that.

Why it matters

If you run PMax for an Australian business, you have been optimising half-blind. Now you can see whether your spend is pouring into cheap Display impressions instead of high-intent Search, and the diagnostics tell you where performance is being dragged down. That is the difference between managing a campaign and hoping it works.

7 channels

Performance Max now reports results across Search, YouTube, Display, Discover, Gmail, Maps and Search partners

What to do about it

Open the channel performance report on every active PMax campaign and turn on the cost toggle. Find out where the money actually goes.
Work the diagnostics column. Treat each flagged issue as a task, not a footnote.
If Display or Gmail is eating budget without converting, use asset and channel controls to steer spend back towards intent.
Download the table and compare channel cost against channel conversions. Kill the assumption that PMax is one thing.

Automation is not the enemy. Flying blind is. Use the instruments Google just handed you.

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Filip Ivanković
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