How Google’s Channel Performance Report Brings Transparency to Performance Max — What Advertisers Should Do Next

Google’s new Channel Performance report for Performance Max (PMax) campaigns gives advertisers a long-awaited look under the hood of Google’s cross-channel automation. The report, covered in detail in Search Engine Land, breaks down impressions, interactions and conversions by channel — Search, YouTube, Display, Discover, Gmail and more — making it easier to see which parts of Google’s inventory are driving value and which may need adjustment. Read the original Search Engine Land article.

Performance Max campaigns run across Google’s full range of inventory, which has historically left advertisers guessing how budget was being allocated. The Channel Performance report changes that dynamic by providing an account-level overview and campaign-level drilldowns — including a Sankey-style Channels-to-Goals flow and detailed tabular data. As Search Engine Land contributor Mike Ryan observes, “The Channel Performance report already addresses one of the most persistent criticisms of Performance Max – that it operates as a black box.”

What the report shows (and what it doesn’t)

At a glance, the report offers two practical views. The account-level summary displays each campaign with nested rows for channels and default columns for standard performance metrics. The campaign-level view includes a large Sankey diagram that maps impressions through interactions to conversions, plus a data table that breaks performance out by channel and ad type (feed-based vs. asset-based) and supports exports.

However, the report is not without limitations. The Sankey diagram’s visual proportions are not volume-proportional — it’s a directional visualization rather than a precise depiction of traffic share. The data table also omits several calculated metrics (conversion rate, CPC, CTR) that analysts often need, requiring an export to compute them manually. Finally, API access and MCC-level reporting are still rolling out, which limits automation for large accounts today.

Why this matters for advertisers

The Channel Performance report provides immediate value in three main ways. First, it reveals which channels are delivering conversions and which are contributing engagement without conversion. Second, it separates feed-based (product feed) ads from asset-based creative, which helps e-commerce marketers understand the role of feed-driven placements like Shopping or Dynamic Product Ads. Third, it clarifies click-through versus view-through conversions, so teams can evaluate the true quality of traffic.

Actionable steps you can take right now

Use the report as more than a curiosity: embed it into your weekly optimization workflow with these specific actions.

1) Segment to compare feed vs. asset ads

In the account-level table, change the segment to “Ads using product data” to see how feed-based ads perform relative to asset-based ads across each channel. Where feed-based ads outperform, prioritize product-focussed creatives and consider feed-only PMax experiments. Where assets outperform, invest in higher-quality images, headlines and video assets targeted to that channel.

2) Separate click-through and view-through conversions

Under Segment > Conversions, compare click-through to view-through performance. If view-through conversions dominate but do not lead to revenue, tighten audiences or adjust bidding to prioritize channels and placements that drive direct engagement.

3) Export and compute the missing ratios

Export the campaign-level table as CSV or to Google Sheets and add calculated columns (Conversion Rate, Cost / Conv., Conv. value / Cost). Use conditional formatting or heatmaps to flag poor placements by volume and efficiency. These calculated metrics are essential for accurate channel comparisons.

4) Audit placements and exclude poor inventory

Use placement reports for Display and YouTube to find low-quality or irrelevant domains and videos. Translate foreign-language placements with =GOOGLETRANSLATE() and categorize content using available AI tools or manual review. Exclude high-volume low-quality placements at the account level to protect brand safety and spend efficiency.

5) Automate and scale when API access is available

Google has confirmed API and MCC-level support are coming. When available, automate exports, build scheduled reports, and integrate channel-level metrics into your dashboards. In the meantime, community scripts (as noted in the Search Engine Land piece) can augment the report with calculated metrics and proportional charts.

How to interpret the Sankey diagram

The Channels-to-Goals Sankey is useful for a high-level understanding of the user journey inside a PMax campaign, but don’t treat it as a precise gauge. Use it to spot patterns — for example, a channel funnel that produces many impressions but few conversions — and then validate with the raw numbers in the export. Because the visual widths are not volume-proportional, always cross-check with the table data before making budget decisions.

Conclusion

Google’s Channel Performance report is a meaningful step toward demystifying Performance Max. It equips advertisers with channel-level visibility that supports better budgeting, creative testing, and inventory management. As Mike Ryan puts it, the report helps address a major critique of PMax’s opacity: “The Channel Performance report already addresses one of the most persistent criticisms of Performance Max – that it operates as a black box.” Use the report as a springboard: export the data, compute the missing ratios, and operationalize the insights into weekly optimization routines to improve efficiency and ROI.

Source: Mike Ryan, Search Engine Land — https://searchengineland.com/google-channel-performance-report-pmax-campaigns-466298