Lesson 1: How GA4's Event Model Works

Welcome to the course

This course teaches you to measure a website properly with Google Analytics 4 (GA4). Each level works in Google's public demo account or in your own property. Each one ends with a report to build and a question to answer.

Please note: this course is independent. Google does not make it, endorse it or sponsor it. GA4 menus, metrics and settings change often. If a screen looks different from what is described here, Google's current Analytics Help pages are the final authority.

In this first level you will:

1. Learn how GA4 records data as events with parameters.
2. See how that differs from the older session-and-hit model.
3. Open the GA4 demo account and look at live event data.

How older analytics worked: sessions and hits

GA4 replaced Universal Analytics (UA), Google's previous version of Analytics. Standard UA properties stopped processing data on 1 July 2023. You may still meet UA ideas in old reports and blog posts, so it helps to know how UA worked.

UA was built around sessions, and each session contained hits. Every hit had a fixed hit type:

• Pageview hits: someone loaded a page.
• Event hits: an interaction such as a click. Each one had exactly three descriptive fields: Category, Action and Label.
• Ecommerce hits: transactions and items.
• Social interaction hits: actions like sharing.

Think of UA as a filing cabinet with fixed drawers. A pageview went in one drawer and an event went in another. If something didn't fit a drawer, you squeezed it into Category/Action/Label.

How GA4 works: everything is an event

GA4 has one principle: any interaction can be captured as an event. There are no separate hit types. A page load, a scroll, a file download and a purchase are all events. Each event has:

1. An event name, which says what happened (for example, page_view).
2. Parameters, which add detail about what happened. Parameters are name–value pairs. GA4 lets you send up to 25 extra parameters with each event, on top of the ones it logs automatically.

GA4 events do not use Category, Action and Label. They use flexible parameters instead.

Sessions still exist in GA4, but they are worked out from events. GA4 records a session_start event, and a session's length comes from the time between its first and last events.

Worked example: one page view, two models

A visitor opens your pricing page.

In UA:

• A pageview hit was sent inside the visitor's session. It sat in the pageview "drawer", separate from any event hits.

In GA4:

• An event called page_view is recorded, with parameters such as:
  • page_location: the full URL, e.g. https://example.com/pricing
  • page_title: e.g. Pricing | Example Ltd
  • page_referrer: the previous URL

The idea that matters: in GA4, a page view is not a special kind of data. It is just one event among many, built the same way as scroll or purchase. This is why GA4 reports are organised around event names and parameters. Later levels build on this.

Task 1: Open the GA4 demo account

Google offers a free demo account with real data, so you can practise without your own website. You need a Google account. If you don't have an Analytics account yet, Google creates one and adds the demo to it.

Do this:

1. Search for the Google Analytics Help article "Demo account" (support.google.com/analytics/answer/6367342).
2. On that page, click the access link for Google Merchandise Store.
3. Sign in with your Google account if prompted.
4. Check the property name in the account selector at the top of Analytics. It should read Google Merchandise Store.

What's in the demo account:

• Google Merchandise Store: an online shop selling Google-branded goods. It has ecommerce website data.
• Flood-It!: a mobile game with app and web data.

What you can and can't do: everyone gets the Viewer role. You can view reports, filter, add dimensions, build segments and create personal reports. You cannot export reports or explorations, edit settings or use the Analytics Data API on this account. You can't break anything, so explore freely.

Task 2: Find events in the Realtime report

The Realtime report shows activity from the last 30 minutes and refreshes continuously.

Do this:

1. Make sure the Google Merchandise Store property is selected.
2. In the left menu, click Reports.
3. Click Realtime.
4. Scroll to the card Event count by event name.
5. Note the event names and their counts. The list is sorted with the most frequent first.
6. Click an event name, such as page_view, to see the parameters sent with it.

The data is live, so your results will differ from another learner's or from yours an hour later. That's expected.

Your report and question

Build: the Realtime report for the Google Merchandise Store property, scrolled to the Event count by event name card.

Answer: Which events in the demo property's Realtime report fired most often in the last 30 minutes?

Write down the top three event names and their counts. Then, for one of them, write one sentence describing what it records and one parameter it carries.

Key takeaways

• UA used sessions made of typed hits (pageview, event, ecommerce, social). Its events used Category, Action and Label.
• GA4 records every interaction as an event with a name and parameters. There are no separate hit types.
• A page view in GA4 is the page_view event, with parameters such as page_location and page_title.
• GA4 builds sessions from events, starting with session_start.
• The demo account gives you Viewer access to the Google Merchandise Store and Flood-It! properties.
• Reports > Realtime shows the last 30 minutes. The Event count by event name card shows which events fire most.
• This course is independent of Google. Check Google's Help pages for the latest menus.