GA4 Event Parameters: A Practical Guide

Parameters are the additional pieces of data that add more context to Google Analytics events. That simple line obscures the fact that GA4 event parameters are one of the most confusing and least intuitive parts about the new Google Analytics.

GA4 event parameters function quite differently from event parameters in Universal Analytics. The process for creating them, viewing them, and using them in reports is all different.

So let’s dig in and develop a solid understanding of what these event parameters are and how we can properly use them. You can read on below, or watch this embedded video to fully understand event parameters within the context of GA4 events. Choose your own adventure!

What Are Event Parameters in GA4?

Parameters provide additional information about the ways users interact with your website. This is according to Google’s support article on the subject. They are one of the most critical parts of understanding GA4 events.

If you want to view the aforementioned Google article you can check here, or read on below for more of a commonsense explanation.

How About a Practical Example?

Let’s say you have set up a GA4 custom event with the help of Google Tag Manager to track internal link clicks. You have named your event internal_link_click. Every time your event tag fires, GA4 will record an event. But what if you want to know more about these link clicks? What if you want to know for example, the specific URL that was clicked? Or the specific text of the link that was clicked? Or the page that the visitor was on when the link was clicked? All of those additional pieces of data are event parameters that you’d want to view along with your event. Without them, your event data won’t help you too much.

We’ll come back to this specific event later in this guide and detail all the steps you need to know to understand how to use them.

How Does GA4 Track Event Parameters?

This where things start to get a little more complicated. Some event parameters are automatically collected by GA4. Many of them are not.

All events will collect a minimum of 5 event parameters. You can see them below.

Here’s a common sense explanation of three of those parameters:

• page_location = The full URL that the visitor was on when the event took place
• page_referrer = The URL of the prior page that the visitor was on before the current page
• page_title = The title tag. For example, the URL of this page is GA4 Event Parameters: How to Understand GA4 Events

But this is only the beginning of event parameters.

What Other Event Parameters Does GA4 Track?

This is a function of what type of event is being tracked.

You may have heard that GA4 has “4 types” of events. The first two types are tracked by default. They are called automatically collected events and enhanced measurement events. The other types of events are called recommended events and custom events.

The 5 parameters above are collected with every event. As we get into recommended events and custom events (where we’re using Google Tag Manager), we get into significantly more parameters. For this to make sense, it’s worth taking a look at how this compares in GA4 vs. Universal Analytics.

How Do Custom Event Parameters Compare in GA4 vs. UA?

Let’s take a look at UA first.

Creating Event Parameters in UA

You could create up to four event parameters for every event in Universal Analytics. In Universal Analytics, event parameters are created with the help of Google Tag Manager.

Those event parameters fit neatly into 4 distinct names: category, action, label, and value. You can see how I used them in the link tracking event I had created in my Universal Analytics property. The event category was hard coded as link_click. Every time this event fired, the event parameter of link_click was sent to identify the “category” of the event. The “action” and the “label” event parameters were variables instead of a hard-coded value. I left the “value” parameter blank.

The “action” parameter filled in a variable for the {{Click URL}}, which was the destination of the click. The “label” parameter is a variable that will pull in the {{Page URL}}, which is a variable that will pull in whatever page the visitor is on when the link is clicked.

These 4 “names” for event parameters are no longer present in GA4.

Creating Event Parameters in GA4

Google Analytics 4 no longer has any reference to category, action, label, or value. Instead, there is a lot more flexibility in terms of what event parameters are sent with each event that is created in Google Tag Manager.

Some people may appreciate this flexibility, while it is simply more confusing without adding value for others. Regardless of what camp you are in, it’s important to know the difference GA4 presents. In the GA4 event below for internal link click tracking, I’ve included two event parameters. The link_url parameter is a variable that will pull in the {{Click URL}} – the destination of the click. The link_text parameter is also a variable and will pull in the text of the link that is clicked.

Part of the flexibility of GA4 events means that event parameters are not required when creating events with Google Tag Manager. This may not always, or often, be a good idea. However, it’s worth knowing that you only need to send one or more event parameter with an event if that particular event needs the additional data that an event parameter provides.

How Many Event Parameters Does GA4 Have?

We’ve already seen that there are five event parameters that are automatically collected with all GA4 events. That’s the minimum. When creating a GA4 custom event, you can add up to 25 event parameters with each single event.

How Many Events Does Google Analytics 4 Have?

There is an unlimited number of distinct events that you can create in Google Analytics 4. However, there is a limit on the length of the event name. It must be 40 characters or less or Google Analytics will not process it. Event parameters must also be named with 40 characters or less. The length of the event parameter value (the specific URL clicked in the case of the link_url parameter) will be cut off it it exceeds 100 characters.

GA4 Event Parameter List

As we mentioned above, there are 5 event parameters that are sent with all events.

Here they are:

• language
• page_location
• page_referrer
• page_title
• screen_resolution

There are also important event parameters that are sent with select enhanced measurement events. Here are some of those important event parameters.

• link_url and link_text track the specific link that was clicked and the text of that link and is sent with the outbound link ‘click’ event.
• search_term tracks the specific terms that were searched on your site and is sent with the view_search_results event.
• video_percent tracks percentage of embedded YouTube videos viewed and is sent with the video progress event.

For more on getting the most out of enhanced measurement, this 1 page cheat sheet might be worth a look.

Enhanced Measurement Event Cheat Sheet

And this is Google’s list of recommended events. You can click each event to see the recommended event parameters that go with each.

How Do You Add GA4 Event Parameters?

When you create a GA4 event in Google Tag Manager, you can add event parameters. Your tag type should be a “GA4 Event” tag. The tag is what will be sending your data to GA4 once it is paired with an appropriate trigger.

In the example below, I’m creating a GA4 event tag for scroll depth tracking. This is actually one of the enhanced measurement events that GA4 will track by default. However, the enhanced measurement event will only track scrolls at a 90% scroll depth. This isn’t sufficient for what I want to see, so I’m creating my own custom scroll tracking tag with an event parameter.

Clicking into “Event Parameters” at the orange arrow will expand the field and allow us to add one or event parameters.

Here’s my GA4 event tag where I’ve added the scroll_depth event parameter for the scroll event. Instead of firing only at 90% scroll depth, this more detailed version will record scroll depth activity at 25%, 50%, 75%, and 90%. In this case, the {{Scroll Depth Threshold}} is the value of the parameter that will record those different scroll depths. If you want to do the same thing with your setup, you can check out this scroll tracking tutorial.

If I wanted to add more event parameters, I could simply hit the “Add Row” button and create parameters that would be sent along with this event.

Can You Modify GA4 Event Parameters?

Yes! You can either change them within Google Tag Manger or you can use a feature to “modify events” within the GA4 interface. Here’s some information about how to modify an event in GA4 if you want to tackle that.

How Do I See Event Parameters in GA4?

Within the GA4 standard reports, the simplest way to see your event parameters is to first look at a list of your events. You can see this below where I’ve clicked into the “Events” report, which is within the “Engagement” reporting section on the left-hand navigation.

We see a list of 11 events in the blue box above. Unlike with Universal Analytics, we can’t just add a secondary dimension to quickly display event Category, Action, Label, or Value. Instead, we can click into a single event name and then explore the associated parameters. Let’s do that for the 9th item on the list: internal_link_click,

Once we click into that event, we will be looking at data exclusive to that event. You can see that below, with various event parameters in the red box that we could measure in the last 30 minutes.

But wait, you say. That’s only the last 30 minutes! That’s not helpful at all. How Can I see my actual data with a longer term horizon and build helpful reports with it?

That’s a great point…and one that made my bang my head into a wall for months. This is where we need to discuss a very important part about GA4: registering event parameters as custom dimensions. Without this step, you will be “blind” to your event parameters.

Why Can’t I See My Event Parameter Data in GA4?

If you’ve created a new GA4 event parameter, you won’t be able to actually see your event parameter data in your long term reports without registering that event parameter as a custom dimension. This is a surprising (and frustrating) new step compared to UA.

To fix this, first access your admin settings via the gear icon in the bottom left corner of GA4.

Next, click “Custom definitions”  within your the property settings.

Now, click the blue “Create custom dimension” button.

From here, you can create a new custom dimension for your event parameter.

This involves a dimension name (the name that you’ll see in your reports, in the green box). An optional description (for your own record keeping, in the blue box). And your event parameter (red box), which must match exactly from what you’ve entered in Tag Manager. For a full overview of this process, you can read more about custom dimensions here or watch the video tutorial.

You can create up to 50 event-scoped custom dimensions in a GA4 property. Once you’ve done this, your event parameter will be added to your list of custom dimensions and you’ll be able to see them in your reports.

Is There a GA4 Event Parameter Report?

There’s not a single place you can go in GA4 to see all your event parameters in a report. However, you can build your own reports that will give you the proper event parameter detail to understand your key events. This is another key difference between UA and GA4. In UA, we had a large collection of prebuilt standard reports that could answer a large percentage of questions we might have. In GA4, the standard reports are not great. What we have instead is an option to build our reports with an “Exploration” or by connecting our data to Google Data Studio.

The video below shows how to create a report in Google Data Studio to show all of our link click data and the necessary event parameters.

Wrapping Up

I hope this helps demystify some of the mystery of GA4 event parameters. Don’t forget that Universal Analytics data will no longer be processed in that platform beginning July 1, 2023. In other words, it’s time we get more comfortable with GA4 if we’re going to keep using Google Analytics after June of 2023.

If you’re still someone learning about GA4 you might want to check this list of updated GA4 questions. You can also subscribe to the Root and Branch YouTube channel for an updated video every week or so. I’ll see you there! There are explainers and tutorials for tracking like this.

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About Root & Branch

Root & Branch is a certified Google Partner agency and focuses on paid search (PPC), SEO, Local SEO, and Google Analytics. Hit the button below to check out YouTube for more digital marketing tips and training resources.