Key Takeaways
- GA4 uses an event-based data model — every interaction is an event, and any event can be marked as a conversion, replacing UA's fixed goal types (destination, duration, pages/session, event).
- Bounce rate is replaced by Engagement Rate in GA4 — a session is 'engaged' if it lasts 10+ seconds, has 2+ pageviews, or includes a conversion event; non-engaged sessions are 'bounced'.
- Linking GA4 to Google Ads is required for audience sharing and conversion import — linking alone doesn't import conversions; you must explicitly import GA4 conversion events in the Google Ads interface.
- GA4 reports require re-learning — the Acquisition > Traffic Acquisition report is the closest UA Channels equivalent; most UA reports don't have direct GA4 equivalents.
- GA4 has a 2-month data retention default (extendable to 14 months) — for long-cycle B2B businesses with long attribution windows, check and extend data retention immediately after setup.
Google Analytics 4 was released in October 2020 alongside a clear signal: Universal Analytics would eventually be sunset. That sunset arrived on July 1, 2023, when UA stopped processing new data — making GA4 the only option for Google Analytics measurement. For PPC advertisers and account managers, GA4 represents a significant shift. The metrics, reports, and data model are fundamentally different from Universal Analytics — and the transition has implications for how conversions are tracked, how remarketing audiences are built, and how campaign performance is analysed. This guide focuses specifically on GA4 for PPC use cases: what changes, how to set up the Google Ads connection, how to configure conversions, and which GA4 reports replace the UA reports you relied on for campaign analysis.
Definition: Events and Parameters in GA4
In Google Analytics 4, an Event is any user interaction or occurrence — page_view, scroll, click, form_submit, purchase, video_play, file_download. Unlike Universal Analytics where events had Category/Action/Label, GA4 events have a name and Parameters — key-value pairs that provide context. For example, a 'purchase' event has parameters: transaction_id, value, currency, items (array). A 'generate_lead' event might have parameters: form_id, form_name. Parameters allow the same event name to describe many different specific interactions. Some events are collected automatically by GA4 (page_view, session_start, first_visit); others are Recommended Events with standard naming (add_to_cart, begin_checkout, purchase); and Custom Events can be created for any interaction the default events don't cover. Conversion events in GA4 are simply events marked as conversions in the GA4 admin — not a separate tracking mechanism.
Setting Up GA4 for Google Ads: Linking, Conversions, and Audiences
The GA4–Google Ads connection involves three steps: linking the properties, configuring conversion events in GA4, and importing those conversions into Google Ads for Smart Bidding.
Linking GA4 to Google Ads is done in GA4: Admin > Property > Google Ads Links > Link. You'll need to be an Editor or Administrator in both GA4 and Google Ads. Once linked, two things become available: GA4 audiences can be published to Google Ads for use in remarketing campaigns (GA4 Admin > Audiences > Create audience > Publish to Google Ads), and GA4 conversion data flows into the Google Ads interface for comparison. Critically, linking does not automatically import conversions for Smart Bidding — that requires a separate step in Google Ads.
To import GA4 conversions into Google Ads: in Google Ads, go to Tools & Settings > Measurement > Conversions > plus button > Import > Google Analytics 4 properties. Select the GA4 property and the conversion events you want to import. Once imported, these conversions appear as Google Ads conversion actions and can be used as the optimisation target for Smart Bidding strategies. If you're running Target CPA or Target ROAS, you'll want to import your primary conversion event (typically 'purchase' for eCommerce, 'generate_lead' for service businesses, 'book_appointment' for booking-based businesses).
For remarketing audiences, GA4 offers more sophisticated audience building than UA — you can build audiences based on sequences of events (users who viewed a product but didn't add to cart), predictive audiences (users likely to purchase in the next 7 days, available for stores with sufficient purchase data), and cross-device audiences (users identified across both web and app). These audiences are published to Google Ads and become available in the Audiences section for remarketing display, YouTube, or search remarketing campaigns.
- GA4 Admin > Google Ads Links > Link — requires Editor access in both properties
- Mark events as conversions in GA4: Admin > Events > toggle 'Mark as conversion'
- Import to Google Ads: Tools > Conversions > Import > Google Analytics 4
- GA4 audience builder: more flexible than UA — event sequences, predictive, cross-device
- Enable auto-tagging in Google Ads for complete utm_campaign/source/medium data in GA4
GA4 Reports for PPC Analysis
GA4's new report structure replaces UA reports — the Traffic Acquisition report is the primary PPC performance view; Explorations (formerly Custom Reports) enable deep analysis.
The Traffic Acquisition report (Reports > Acquisition > Traffic Acquisition) is GA4's equivalent of UA's Channels report — it shows sessions, engaged sessions, engagement rate, conversions, and revenue broken down by default channel group (Paid Search, Organic Search, Direct, Referral, etc.). By default, this report shows sessions by channel group; switch the primary dimension to 'Session Google Ads campaign' to see Google Ads campaign-level data. The key difference from UA: GA4 defaults to 'Sessions' and 'Engaged sessions' rather than 'Sessions' and 'Bounce Rate'.
For deeper PPC analysis — ad group level, keyword level, device breakdown — use Explorations (the left nav compass icon). Explorations are GA4's flexible analysis workspace replacing UA's custom reports and multi-channel funnels. Create a Free Form exploration with Session Google Ads campaign, Session Google Ads ad group name, or Session keyword as the row dimension, and Conversions, Revenue, Engagement Rate as metrics. GA4 also has a built-in Funnel exploration that shows the conversion path from landing page to thank-you page — useful for identifying which landing pages lose the most users in the conversion funnel.
One important caveat: GA4 sampling — GA4 uses sampling in Explorations for large datasets, which can affect the accuracy of ad hoc reports. For high-volume PPC accounts (millions of sessions), sampling may produce significantly different numbers than the actual data. The standard reports (Traffic Acquisition, Conversions) are unsampled; the issue appears specifically in Explorations with large date ranges or many dimensions. If sampling is affecting critical reports, Google Analytics 4 360 (the paid tier) offers unsampled Explorations.
Experience Signal
The GA4 transition that causes the most disruption for PPC teams is the conversion tracking changeover — particularly for accounts that used UA's destination goals (tracking a thank-you page URL as a conversion). In GA4, destination-based conversions are configured as 'page_view' events with the page_location parameter matching the thank-you URL, then marked as a conversion. This is functionally equivalent but requires verification that the event is actually firing. The accounts where we see the biggest issues are those that linked GA4 to Google Ads but forgot to import conversions — Smart Bidding defaults to optimising towards all conversion events if no specific events are selected, which can include low-value micro-conversions (scroll, page_view) that shouldn't drive bidding decisions.
Frequently Asked Questions
Universal Analytics (UA) uses a session-based data model — it groups user activity into sessions and measures metrics like sessions, pageviews, and session duration. Google Analytics 4 (GA4) uses an event-based data model — every user interaction (pageview, button click, form submission, scroll, video play) is an event with associated parameters. This change affects: how conversions are defined (any event can be a conversion in GA4), how audiences are built (based on events and parameters rather than session conditions), and how data is reported (no sessions in GA4 — engagement rate replaces bounce rate). GA4 also has cross-device tracking (unified measurement across web and app), longer data retention options, and deeper Google Ads integration. Universal Analytics stopped processing new data on July 1, 2023.
In GA4: Admin > Google Ads Links > Link. You'll need Google Ads link permissions. Once linked: GA4 audiences become available in Google Ads for remarketing targeting, GA4 conversion events can be imported into Google Ads as conversion actions, and Google Ads campaign data flows into GA4 reports. Important: linking GA4 to Google Ads doesn't automatically import conversions — you must explicitly import the GA4 conversion events you want Google Ads to optimise toward (in Google Ads: Tools & Settings > Conversions > Import > Google Analytics 4). Also enable auto-tagging in Google Ads to ensure GA4 receives the full campaign, ad group, and keyword data from clicks.
GA4 conversions can be imported into Google Ads and used as the optimisation target for Smart Bidding strategies (Target CPA, Target ROAS, Maximize Conversions). The mechanics are the same — Smart Bidding optimises toward the conversion actions you specify. The change is in how conversions are defined: in GA4, any event can be marked as a conversion, giving more flexibility than UA's goal types. Cross-device measurement in GA4 may also provide more complete conversion data to Smart Bidding, particularly for businesses where customers research on mobile and convert on desktop — more complete attribution data typically improves Smart Bidding performance over time.
Sources
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Jai Paek
Creative Director
Jai leads brand identity and UX design at Webnixon, bringing 20+ years of experience building digital design systems for agencies and enterprise teams. He has shipped design systems and visual identities for over 200 brands across Canada and the US, with deep expertise in conversion-focused UI, WCAG 2.1 accessibility compliance, and responsive web design for service businesses and ecommerce brands.
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