Google Ads Performance Max Analytics: Metrics and What the Data Actually Shows

Google Ads Performance Max Analytics: Metrics, Reporting, and What the Data Actually Shows

Google Ads Performance Max campaigns give you ROAS, CPA, conversion volume, impressions, clicks, and asset group performance - but they deliberately hide placement-level data, keyword-level attribution, and channel-by-channel spend breakdown. When connected to Prooflytics, PMax campaigns appear in your daily brief alongside Standard Shopping and Search campaigns, so you can see whether your automated campaign is outperforming your managed campaigns before Google's interface incentivises you to trust the aggregate.

Performance Max replaced Smart Shopping and Local campaigns in September 2022. Every major ecommerce and lead-gen account now runs at least one PMax campaign - and most teams are making budget decisions with less data than they had before the migration.

Performance Max (PMax): Google's fully automated campaign type that serves ads across Search, Shopping, YouTube, Display, Gmail, Discover, and Maps from a single campaign. Google's AI controls bidding, placements, and targeting. Advertisers supply assets (images, headlines, descriptions, videos) and a conversion goal; Google allocates the rest.

Asset group: the PMax equivalent of an ad group. Each asset group contains a set of creative assets (headlines, images, descriptions, videos) that Google combines and serves across placements. A single PMax campaign can contain multiple asset groups, each targeting a different product category or audience signal.

Placement insights: a limited report in Google Ads (under Insights to Placements) showing which websites, apps, and YouTube channels received PMax impressions. Available but non-actionable - you cannot exclude placements at the asset group level directly.

Key takeaways

Performance Max replaced Smart Shopping and Local campaigns for all advertisers in September 2022

Every major ecommerce and lead-gen account now runs at least one PMax campaign. The replacement came with significantly less placement-level visibility than the campaigns it replaced.

PMax deliberately hides placement-level data, keyword attribution, and channel-level spend breakdowns

This is the primary data gap versus Standard Shopping and Search campaigns. Advertisers who valued placement-level diagnostics from Smart Shopping lost that capability at the mandatory migration.

Performance Max delivers 15 to 20 percent higher ROAS than Standard Shopping according to Google's own benchmarks

This is a self-reported figure without placement-level verification. Whether the improvement holds after accounting for attribution model changes and cross-channel credit claims is not independently verified.

The Search Terms Insight report shows query clusters driving conversions without individual search terms

This is the best available diagnostic tool for PMax traffic quality, available under the Insights tab. It reveals the intent clusters that drive conversions at the category level, not the keyword level.

Asset group performance data available since October 2023 shows which creative combinations Google favors

The data reveals which assets are being served but not at what cost per conversion or on which placements. It is an execution signal, not a true creative performance diagnostic.

What data is actually available from a Performance Max campaign

The operational frustration for in-house performance teams running PMax: the campaign shows a clean aggregate ROAS, but the data behind it is intentionally opaque. Here is what you can and cannot see.

What PMax reports (available in Prooflytics via Google Ads sync):

• Total impressions, clicks, and CTR across all Google channels
• Total spend and CPA at the campaign level
• Conversion volume and ROAS at the campaign level
• Asset group performance (which combinations Google is serving most)
• Search themes and category-level search term insights (broad topic groups, not specific queries)
• Audience signal engagement (which audience lists attracted conversions)
• New vs. returning customer segmentation (available with audience lists and conversion goals configured)

What PMax does not report (intentional black box):

• Keyword-level data - PMax generates its own search terms; you cannot see which exact queries triggered ads
• Channel-level spend breakdown - no way to see how much went to YouTube vs Shopping vs Display
• Individual placement exclusions - you can exclude content categories and sensitive topics but not specific URLs
• Product-level ROAS from Shopping inventory (visible in some accounts via product group supplemental reports, not universal)

The practical effect: a PMax campaign showing 7x ROAS may be generating most of that return from branded search (high-intent users who would have converted organically) while wasting 40% of spend on Display placements at 1x ROAS. The aggregate hides the cross-channel allocation.

The attribution inflation problem with Performance Max

The ICP problem this creates for ecommerce performance teams: PMax systematically over-claims credit for conversions - and most Google Ads dashboards display the over-claimed number without flagging it.

PMax operates on a 30-day click attribution window by default. When a user searches your brand name after seeing a YouTube ad, PMax claims the conversion. When a user converts after visiting your store organically and then clicking a Shopping ad that ran in the same PMax campaign, PMax claims it. The campaign that "serves everywhere" naturally appears at some touchpoint in most conversion paths - and last-click or data-driven attribution within Google's ecosystem assigns much of the value there.

Independent measurement consistently shows a 20-35% gap between PMax-reported conversions and conversions attributable to PMax from platform-neutral tools (Northbeam, Triple Whale, GA4 with cross-channel last-click). The gap is larger for accounts where PMax shares budget with Search and Shopping and where brand search volume is high.

The practical implication: when Prooflytics surfaces PMax ROAS alongside your Meta ROAS and GA4-attributed revenue, the PMax number will typically look better than what a platform-neutral attribution model would show. Prooflytics displays PMax ROAS from Google Ads reporting alongside your GA4 attribution data when both are connected - so you can see both the platform-reported number and the GA4-modelled number before making a budget decision.

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Performance Max vs Standard Shopping: the comparison that actually matters

If you run both PMax and Standard Shopping, the daily comparison that matters is ROAS, CPA, and impression share - not the aggregate ROAS each campaign reports individually.

PMax benchmarks (ecommerce, 2025-2026):

• Average ROAS: 6-12x for established ecommerce accounts with 50+ monthly conversions
• Average CPA: varies by category; fashion £8-15, electronics £18-35, home goods £12-22
• Impression share: PMax typically captures higher impression share than Standard Shopping for the same budget because it accesses more inventory types

Standard Shopping benchmarks (for comparison):

• Average ROAS: 4-8x - 15-20% lower than PMax on equivalent budget
• CPA: slightly higher per conversion, but conversion quality may differ
• Impression share: limited to Search/Shopping placements; more predictable

What the comparison does not tell you: PMax's higher ROAS may reflect cannibalism (PMax is capturing conversions that Standard Shopping would have generated at lower cost) rather than incremental efficiency. The cleanest test is a holdout experiment using Google Ads' built-in Campaign Experiments - run PMax against Standard Shopping with a held-out budget split and measure incrementally over 4-6 weeks.

Prooflytics shows PMax and Standard Shopping ROAS and CPA side-by-side in the daily Google Ads channel view, so you can see trend divergence without exporting from Google Ads first.

Performance Max relies heavily on Smart Bidding, which optimizes against whatever conversion signal you provide. Bad conversion tracking, weak creative, or misconfigured audiences produce mechanical failure at scale. The fix is upstream of the bidding strategy, not in it. See why Smart Bidding does not save bad Google Ads campaigns.

How to extract more signal from Performance Max campaigns

Given the data limitations, three adjustments make PMax campaigns more measurable without Google increasing reporting access:

1. Segment by new vs returning customers. PMax defaults to optimising for all conversions. Adding an audience list of existing customers (from your CRM or Shopify customer list) and configuring "new customer acquisition goal" allows PMax to report new vs returning customer conversions separately. For DTC brands, new customer ROAS is the only number that matters for growth accounting.

2. Use brand exclusions to isolate paid contribution. PMax will harvest branded search without brand exclusions. Excluding your brand terms from PMax forces the campaign to generate conversions from non-brand queries - making the ROAS number a more honest picture of paid acquisition efficiency. The downside: total PMax conversions will drop, often 20-40%, revealing what fraction of PMax "wins" were branded.

3. Monitor impression share by campaign type. When PMax impression share rises and Standard Shopping impression share falls simultaneously, it typically means PMax is cannibalising your Shopping budget - both campaigns bidding on the same queries with PMax winning because it accepts higher CPCs. Prooflytics flags this pattern when impression share trends diverge by more than 10 percentage points week-over-week between PMax and Standard Shopping.

How to connect Performance Max to Prooflytics

Performance Max campaigns sync automatically as part of the Google Ads integration - no separate configuration needed.

Step 1. Go to Settings to Data Sources in your Prooflytics dashboard and open the integrations panel.

Step 2. Find Google Ads and click Connect if not already connected.

Step 3. Authenticate with the Google account that has access to the Google Ads account managing PMax campaigns. Read-only access is sufficient.

Step 4. In the campaign selector, PMax campaigns appear as campaign type "PERFORMANCE_MAX" - they sync alongside Search, Standard Shopping, and Display campaigns automatically.

Step 5. Data appears in your next morning briefing. Prooflytics shows PMax separately in the campaign breakdown, labelled by campaign name and type, so you can see its ROAS and CPA isolated from other campaign types.

Most common question: if your PMax ROAS in Prooflytics looks lower than in Google Ads, check the date range and conversion window. Google Ads defaults to 30-day click plus 1-day view attribution; Prooflytics syncs the same attributed data from the API but may show a different window if you've customised your conversion action attribution settings.

Bottom line

• PMax reports ROAS, CPA, and conversion volume at the campaign level - but not keyword, channel, or placement-level data; those are intentionally hidden
• The attribution inflation problem: PMax claims credit for branded and last-touch conversions it did not generate; independent measurement shows 20-35% overstatement is typical
• Add brand exclusions and new customer acquisition goals to make PMax ROAS more interpretable
• Compare PMax vs Standard Shopping daily - when impression share diverges by 10+ pp, PMax is likely cannibalising Shopping budget
• Prooflytics syncs PMax automatically via the Google Ads integration and shows it separately from other campaign types in the daily brief

You can read independent reviews of Prooflytics on G2 and compare it to alternatives in the marketing analytics category.