Question

After launching PMax, I’m having a hard time tracking performance by channel in GA4. I can’t clearly see how much traffic or conversions are coming from Shopping vs Display vs YouTube inside PMax. Is there a way to split it out more granularly for reporting?

Answer 1

This is one of the biggest frustrations with Performance Max, by default, Google lumps all its placements (Shopping, Display, YouTube, Search, Discover) together, so GA4 and Google Ads don’t give you clean channel-by-channel breakdowns.
But you can get closer to granular reporting with a few workarounds.

Why You Can’t See Channel-Level Data in PMax by Default

• PMax is cross-channel by design — Google decides where to show ads based on its algorithm, not on your manual channel splits.

• GA4 gets the traffic tagged as a mix of “Paid Search,” “Display,” “Video,” etc., only if the UTM structure is set up to differentiate.

• In native Google Ads reporting, the “Performance by Network” columns in PMax are very limited (and often sampled).

Workarounds to Break Down PMax Performance by Channel

1. Use Placement/Performance Reports in Google Ads

• Go to Reports → Predefined Reports → Performance Max → Performance by Asset Group / Placement.

• This gives hints on whether impressions/clicks came from YouTube, Display, or Shopping — but it’s still partial.

2. Tag Asset Groups with Custom UTM Parameters

• In each asset group’s Final URL, append channel-specific UTMs so GA4 can break them apart.

Example for Shopping asset group:
?utm_source=google&utm_medium=shopping-pmax&utm_campaign=pmax_q3&utm_content=assetgroup_shopping

For YouTube:
rce=google&utm_medium=video-pmax&utm_campaign=pmax_q3&utm_content=assetgroup_youtube

• In GA4, filter by these UTMs to see traffic/conversions from each group.

3. Split PMax Into Multiple Campaigns by Channel Focus

• While you can’t force “Shopping only” in PMax, you can make asset groups that only have Shopping feeds or only have video assets — and run them in separate campaigns.

• This way, each campaign becomes your “channel bucket” for reporting.

4. Use the “Performance by Listing Group” Report for Shopping

• For eCommerce accounts, under PMax, you can view Listing Group reports to isolate Shopping-specific performance.

• This will not cover Display or YouTube, but it gives you clean Shopping numbers.

5. Use GA4 Exploration Reports

• In GA4, create a free-form Exploration with:

  • Dimension: Session source/medium or UTM content

  • Dimension: Landing page

  • Metric: Conversions

• If your UTMs are set correctly per asset group, this will show your PMax traffic split.

Pro Tip:
If you want this to be bulletproof, set up UTM auto-tagging overrides + Google Ads Labels for each asset group, then build a Data Studio (Looker Studio) dashboard combining GA4 and Ads API data. That way, you’ll have a near-true channel-level breakdown for PMax.