What is Google Analytics 4 (GA4)?
Google Analytics 4 is the free Google tool that measures what people do when they reach your site and your app. What separates it from the previous version is that it records everything as an event rather than a page view. Purchases, form submissions and clicks are all measured inside the same structure.
GA4 is the current version of Google Analytics. The previous version, Universal Analytics, was shut down in 2023. Sites with an older setup were migrated, and every newly created site now uses GA4 directly.
The difference is not only the interface, it is the measurement logic. The old version read the world through sessions and page views. GA4 reads it through events, a model that takes time to get used to but is more flexible in the end.
What event-based measurement means
In the old version, opening a page and clicking a button were two different concepts. In GA4 both are events, only their names and the information they carry differ.
The extra information an event carries is called a parameter. A purchase event, for example, carries value and currency parameters. Most reports are built on those parameters.
In the old version | Equivalent in GA4 |
|---|---|
Page view | page_view event |
Event category, action, label | Event name and parameters |
Goal | Key event |
View | Gone, replaced by data streams and filters |
Data streams and setup
In GA4 the unit of measurement is called a property and the data entry point is called a data stream. A website and a mobile app can be two separate streams under the same property and are read together in reports.
Create a property at analytics.google.com
Add a web data stream and enter your site address
Add the measurement code you are given to your site, or connect it through your tag manager if you use one
Open the Realtime report and watch your own visit, this is how you know the setup works
Mark important events such as purchase or form submission as key events
Skipping the key event marking is the most common setup mistake. The event is recorded but does not behave like a conversion in reports and cannot be passed to the advertising side.
The first reports to look at
Acquisition: which channel the visitor came from, organic search, paid or direct
Engagement: which pages are actually read and which events fire
Monetization: purchases and revenue, if you have e-commerce set up
Realtime: only useful while verifying a setup, not suitable for daily decisions
Three things people often confuse in GA4
The first is data delay. Standard reports usually settle within twenty-four hours, so today's figure looks incomplete, and that is not an error.
The second is the data retention period. The default is two months and it can be raised to fourteen months in settings. Sites that forget to change it cannot compare against the same period a year earlier.
The third is thresholding. On small data sets Google hides some rows, so totals and the sum of the breakdowns may not match.
Why it matters if you run ads
GA4 shows the side the ad platform cannot see: what happened after the click. The ad platform knows the click and the conversion, but not the page where the user gave up.
Once it is linked with Google Ads, the campaign breakdown lands in GA4 reports and key events defined in GA4 can be passed to the advertising side. You can find how that connection is made in the article where we walk through it step by step.
Sources
Frequently asked questions
Is GA4 free?
Was my Universal Analytics data moved into GA4?
Where are conversions in GA4?
Why do the numbers differ from my ad platform?
How do I extend the data retention period?
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