Quick Answer
- GA4 is Google's current analytics platform. It replaced Universal Analytics, which was shut down on July 1, 2023.
- GA4 records every user interaction as an event, not as a session or pageview. That shift changes how you read and act on the data.
- You designate specific events as "Key Events" to tell GA4 and Google Ads what actually matters to your business.
- GA4 connects directly to Google Ads, so your campaigns can optimize toward those Key Events instead of clicks.
- Default GA4 reports are a starting point, not the finish line. You will need to configure them to answer real business questions.
- GA4 alone does not solve data loss from ad blockers or browser privacy restrictions. That requires a separate server-side tracking layer.
What Is GA4?
GA4 is Google's current analytics platform, built on an event-based data model that records every user interaction, from a pageview to a button click to a form submission, as a distinct event.
Google Analytics 4 is the version of Google Analytics that exists now. If you set up a new analytics property today, GA4 is what you get. If you were running Universal Analytics before July 2023, that property stopped collecting data and GA4 is your only path forward.
The "4" reflects that this is the fourth generation of the product. But it is not just an update. The underlying architecture is fundamentally different from every version that came before it. Understanding that difference is the only way to read GA4 data correctly.
How GA4 Is Different from Universal Analytics
Universal Analytics was sunset by Google on July 1, 2023, making GA4 the only supported Google Analytics property for new data collection.
Universal Analytics organized everything around sessions. A session was a visit. Pageviews happened inside sessions. Goals fired when a specific condition was met inside a session. The entire reporting language was built on that frame.
GA4 throws out the session as the primary unit and replaces it with events. Every single thing a user does on your site or app is recorded as an event: a page load, a scroll, a video play, a click on a phone number, a form submission. Sessions still exist in GA4, but they are derived from events rather than being the foundation.
This matters for a few practical reasons.
First, cross-device tracking is more reliable. When a user visits on a phone on Tuesday and comes back on a laptop on Thursday, Universal Analytics often counted those as two separate users. GA4 is designed to stitch that journey together using Google signals and user ID, giving you a more accurate picture of how many real people are actually converting.
Second, you have more granular data by default. GA4 automatically collects events like first_visit, session_start, scroll, and click without you having to configure them manually. That is a meaningful jump from Universal Analytics, where many of those required extra tag setup.
Third, the data model is closer to what Google Ads already uses internally. That alignment makes the connection between your analytics and your ad campaigns tighter and more actionable.
Key Events (Conversions) and Why They Actually Matter
In Universal Analytics, you set up Goals. A Goal fired when a user completed a specific action, such as reaching a thank-you page or spending a minimum amount of time on site. Goals were binary: met or not met.
GA4 replaced Goals with Key Events. The concept is similar but the mechanics are cleaner. Any event in GA4 can be marked as a Key Event. When you do that, GA4 reports on it prominently, and more importantly, you can import it into Google Ads as a conversion action.
In GA4, you designate specific events as Key Events, which tells both GA4 and Google Ads to treat those interactions as meaningful business outcomes worth optimizing toward.
What should be a Key Event? The answer depends on your business model, but the general principle is: mark the events that are closest to actual revenue. For a law firm, that is a form submission or a qualified phone call. For an ecommerce store, that is a completed purchase. For a home services company, it is a booking or a lead form completion.
What should NOT be a Key Event: scroll depth, time on page, or a visit to a blog post. Those are engagement signals. They are useful for understanding behavior, but if you import them into Google Ads as conversion actions, Google's bidding algorithms will optimize toward readers, not buyers.
This is one of the most common and most expensive mistakes in Google Ads management: marking soft engagement as a conversion and then wondering why CPA (cost per acquisition) keeps climbing while actual leads stay flat.
The Reports That Actually Answer Business Questions
GA4's default reporting interface can feel overwhelming the first time you open it. The left nav has more sections than most people ever need to touch. Here is a practical map of where to spend your time.
Reports Snapshot
The home screen gives you a quick read on users, sessions, and revenue (for ecommerce). It is useful for a daily sanity check: did traffic move meaningfully in either direction today? If yes, dig deeper. If no, move on.
Acquisition Reports
Under Reports > Acquisition, you will find two views: User Acquisition and Traffic Acquisition. User Acquisition shows how users first found you. Traffic Acquisition shows the source of each session.
For most businesses, the most useful question here is: which channels are driving sessions that convert? The default view does not answer that directly. You need to add a secondary dimension or use the Explorations feature (described below) to cross-reference acquisition source with Key Event completions.
Engagement Reports
This section tells you which pages users visit, how long they stay, and which events fire most often. The Pages and Screens report is the most immediately useful: it shows you which pages are getting traffic, what the engagement rate is, and which pages are tied to Key Event completions.
Engagement rate in GA4 replaced bounce rate from Universal Analytics. An engaged session is one that lasts longer than 10 seconds, has a conversion event, or has at least two page views. The engagement rate is the percentage of sessions that qualify. A high engagement rate on a landing page combined with a low Key Event completion rate is a signal worth investigating: people are staying, but something is stopping them from converting.
Monetization Reports
If you run an ecommerce store with GA4 ecommerce tracking enabled, this section shows you revenue, transactions, average order value, and funnel drop-off. If you are not running ecommerce tracking, this section will be largely empty.
Explorations
This is where GA4 becomes genuinely useful for analysis. Explorations is a free-form workspace where you can build custom reports. The most useful template for most advertisers is the Funnel Exploration: define the steps you expect users to take (landing page, product page, cart, checkout, purchase), and GA4 shows you exactly where users drop off.
Imagine a home services company running Google Ads to a landing page. A Funnel Exploration built around that flow, from first visit to form submission, will show whether the drop-off is happening at the landing page (a traffic quality or page relevance problem), the form itself (a UX or friction problem), or the thank-you confirmation (a tracking problem). Each diagnosis leads to a different fix.
Connecting GA4 to Google Ads
GA4's integration with Google Ads means that campaigns can optimize toward actual conversions rather than clicks or sessions, which changes how Google's bidding algorithms allocate your budget.
The connection between GA4 and Google Ads is one of the most important steps in any properly built campaign. When your Google Ads account is linked to your GA4 property and you import Key Events as conversion actions, Google's bidding strategies, specifically Target CPA and Target ROAS, have a real signal to learn from.
Here is why this matters in practice. Google's smart bidding algorithms work by finding patterns in historical conversion data. They look at signals like time of day, device type, audience membership, geographic location, and query intent, and they adjust bids in real time to maximize the probability of a conversion. The quality of that optimization is entirely dependent on the quality of your conversion data.
If your conversion signal is a form submission on a thank-you page, Google is optimizing toward form submitters. If your conversion signal is scroll depth or a PDF download, Google is optimizing toward engaged readers. The campaigns will perform very differently, and that difference compounds over time as the algorithm accumulates more data.
To link GA4 to Google Ads, you go to Admin > Product Links > Google Ads Links in GA4, connect your account, and then enable personalized advertising and conversion imports from the Google Ads side. Once linked, you can import Key Events directly into Google Ads as conversion actions under Tools > Conversions > Import > Google Analytics 4.
One practical note: when you import a GA4 Key Event into Google Ads, Google Ads treats it as a secondary conversion action by default. You have to manually set it as a primary conversion action if you want smart bidding to optimize toward it. Leaving it as secondary means it gets reported but does not influence bidding. This is a small configuration step that many setups miss.
Common GA4 Setup Mistakes
One of the most common GA4 setup mistakes is leaving the property in its default state without marking any events as Key Events, which means Google Ads has no conversion signal to learn from.
These are the mistakes we see most often when auditing GA4 setups.
No Key Events marked. GA4 collects data by default, but nothing is a Key Event until you tell it to be. If no Key Events are marked, your Google Ads campaigns are running without a conversion signal. Google is spending your budget but has no feedback loop to learn from.
Thank-you page redirect not working. The most common way to track a form submission is to redirect the user to a thank-you page after they submit, and fire an event on that page. If the redirect is broken or the event fires on the form page instead of the confirmation page, you will see inflated conversion numbers. Every page load that goes to the form URL counts as a conversion, not just successful submissions.
Incorrect attribution model. GA4 defaults to a data-driven attribution model, which distributes credit across multiple touchpoints. Universal Analytics defaulted to last-click. If you are comparing GA4 numbers to old UA numbers and expecting them to match, they will not. The attribution models are different by design.
Self-referral traffic pollution. If your payment processor or booking tool redirects users back to your domain and it is not listed as a referral exclusion in GA4, those sessions will show as "referral" traffic. Your paid traffic attribution gets diluted, and your channel reporting becomes unreliable.
No internal IP filtering. If you and your team visit the site regularly and those sessions are not filtered out, your engagement metrics will include non-customer behavior. For smaller sites, this can meaningfully skew the data.
When GA4 Alone Is Not Enough
GA4 alone cannot recover conversion data that is blocked by ad blockers or lost due to browser privacy restrictions; a server-side tracking layer is needed to capture that signal.
GA4 fires tags through the user's browser. That means every ad blocker, browser privacy extension, and iOS Intelligent Tracking Prevention rule has an opportunity to block or degrade your tracking data. For sites with audiences that skew tech-savvy, the gap between GA4-reported conversions and actual conversions can be significant.
The fix is server-side tracking. Instead of firing tags from the browser, server-side tracking routes the data through your own server before sending it to GA4 and Google Ads. Ad blockers cannot reach your server. Browser privacy rules do not apply to server-to-server calls. The result is a more complete, more accurate conversion record.
Server-side tracking is not a GA4 setting. It requires a separate infrastructure layer, typically built in Google Tag Manager Server-Side or a third-party consent and data pipeline tool. It is the right investment for any advertiser spending enough that data accuracy has a direct impact on bidding quality and ROAS reporting.
GA4 is also not a CRM replacement. It tells you that a form was submitted. It does not tell you whether that lead became a paying customer. Closing the loop between GA4 conversion data and actual revenue requires connecting GA4 to your CRM, either directly or through a data pipeline, so you can see which campaigns produced revenue, not just leads.
That full-funnel view, from ad click to signed customer, is the standard we build every tracking system toward at RGDM. If your current setup stops at the form submission and you want to see what actually happened to those leads, our analytics and tracking service is the right place to start.
Frequently Asked Questions
What is GA4?
GA4 (Google Analytics 4) is Google's current analytics platform. It records user interactions as events rather than sessions or pageviews, and it works across both websites and mobile apps. Google shut down Universal Analytics on July 1, 2023, making GA4 the only supported option for new data collection.
How is GA4 different from Universal Analytics?
Universal Analytics organized data around sessions and used Goals to track conversions. GA4 organizes data around events and uses Key Events. GA4 also offers improved cross-device tracking, a closer integration with Google Ads, and a free-form Explorations workspace for custom analysis. The two platforms use different attribution models and different session definitions, so historical data from Universal Analytics does not directly compare to GA4 data.
What are Key Events in GA4?
Key Events are specific events that you mark as meaningful business outcomes inside GA4. Any event can be made a Key Event. When you import a Key Event into Google Ads as a primary conversion action, Google's smart bidding algorithms optimize toward that action. If nothing is marked as a Key Event, Google Ads has no conversion signal to learn from.
How do I connect GA4 to Google Ads?
Link the accounts under Admin > Product Links > Google Ads Links inside your GA4 property. Once linked, go to your Google Ads account, navigate to Tools > Conversions > Import, and import your GA4 Key Events. Set the imported actions as primary conversion actions so smart bidding uses them for optimization.
Why does GA4 show fewer conversions than Google Ads?
Attribution model differences account for some of the gap. GA4 uses data-driven attribution by default, which distributes credit across multiple touchpoints. Google Ads may use a different model depending on your settings. Data loss from ad blockers and browser privacy rules also contributes. A server-side tracking layer reduces the gap by capturing conversion signals that browser-based tags miss.
Can GA4 track phone call conversions?
GA4 can track a click on a phone number link as an event, but it cannot track whether the call connected or lasted long enough to qualify as a lead. For proper call tracking, you need a call tracking integration, such as Google Ads call extensions with call reporting enabled or a third-party tool that assigns dynamic numbers to traffic sources and reports back into GA4 and Google Ads.
What is the Explorations feature in GA4?
Explorations is GA4's free-form analysis workspace. It lets you build custom reports using templates like Funnel Exploration, Path Exploration, and Segment Overlap. Funnel Exploration is the most immediately useful for advertisers: it lets you define the steps in your conversion path and shows exactly where users drop off, so you can diagnose whether a problem is in traffic quality, page experience, or tracking.
Is GA4 free?
The standard GA4 property is free to use. Google also offers Google Analytics 360, an enterprise-tier version with higher data limits, a service-level agreement, and BigQuery export included. For most small and mid-size businesses, the free version is sufficient, provided it is configured correctly.
What data does GA4 collect automatically?
GA4 automatically collects a set of events without any additional configuration, including page_view, first_visit, session_start, user_engagement, and scroll. Enhanced Measurement, which is enabled by default for web streams, also automatically tracks outbound clicks, site search, video engagement, and file downloads. These automatic events are useful starting points, but they are not Key Events until you designate them as such.
When should I consider server-side tracking on top of GA4?
If your audience is likely to use ad blockers or privacy-focused browsers, or if your campaigns are running at a scale where missing conversion data materially affects bidding quality, server-side tracking is worth implementing. It is also the right infrastructure for any advertiser who needs to close the loop between marketing data and CRM revenue data, since server-side pipelines can route enriched event data to multiple destinations simultaneously.
If your GA4 setup is collecting data but not answering the questions your campaigns actually need, that is a configuration problem, not a GA4 limitation. Book a strategy call and we will audit your tracking stack, identify where the signal is breaking down, and build the pipeline that ties spend to revenue.