What is performance max structure?
Performance Max (PMax) is Google's automated campaign type, and structurally it has no ad groups and no keywords, unlike a Search campaign. You instead build 'asset groups' (headlines, images, video, text) and let Google's system decide where to show them and what to match them against. That means you can't see which search terms or keywords actually triggered a given result, so troubleshooting has to work through broader signals like asset group performance and audience signals, not keyword-level cause and effect.
In a Search campaign, the unit you diagnose is the keyword: you can see the exact search term that triggered your ad, check its match type, and pause or adjust bids on that specific keyword. Performance Max removes that layer entirely. Google's system decides in real time which of its inventory (Search, Display, YouTube, Gmail, Maps, Discover) to serve your asset combinations against, using its own targeting logic rather than a keyword list you control. There is a 'search terms insights' report that gives some visibility into search category themes, but it's a coarser, aggregated view, not a row-by-row list of exact queries with individual performance data the way a Search campaign's search terms report is.
This is why 'PMax is underperforming' is a harder problem to diagnose than 'this Search campaign is underperforming.' You can't isolate a bad keyword and fix it. What you can do is look at asset group-level performance, check which audience signals you fed the campaign, review the search category themes report for obvious mismatches, and examine which conversion actions are being optimized toward. If a beginner or someone burned by a failed campaign associates 'not working' with 'I couldn't find the problem,' the PMax structure is often literally why. The visibility isn't hidden by someone withholding it from you; it's a structural consequence of an automated, cross-network campaign type that doesn't operate on a keyword layer at all.