Event Parameters in Google Analytics 4 (GA4) are the additional information about an event that is sent along with the event.

There are three types of event parameters in Google Analytics 4

#1 Automatically Collected Parameters

#2 Custom Parameters

#3 User properties

#1 Automatically Collected Parameters

Some parameters are automatically collected by GA4. Such parameters are called automatically collected parameters.

For example, by default, GA4 records the following parameters with every event:

1. language
2. page_location
3. page_referrer
4. page_title
5. screen_resolution

How to see automatically collected parameters in GA4 reports?

Follow the steps below:

Step-1: Navigate to your GA4 reporting view.

Step-2: Click on ‘Events’ (under ‘Engagement’):

 

Step-3: Scroll down and then click on an event name. Let’s click on the ‘page_view’ event:

You should now see the detailed report about the ‘page_view’ event:

 

Step-4: Click on the ‘PARAMETER NAME’ drop-down menu on the right hand side:

 

Step-5: Scroll down the drop-down list and then you should be able to see all the automatically collected parameters:

#2 Custom parameters

You can also manually send one or more parameters along with an event via GTM. Such parameters are called ‘Custom parameters’.

There are two types of custom parameters:

#1 Text parameters
#2 Number parameters

#2.1 Text parameters

The value of such parameters is not a number.

You can register text parameters as custom dimensions in the GA4 user interface. But you should not register them as custom metrics.

If you want to use text parameters in your GA4 reports then you would need to register them as custom dimensions in the GA4 user interface.

#2.2 Number parameters

The value of such parameters is a number.

You can register number parameters as custom metrics in the GA4 user interface. But you should not register them as custom dimensions.

If you want to use number parameters in your GA4 reports then you would need to register them as custom metrics in the GA4 user interface.

Note: Event category, Event action, Event label and Event Value parameters are used in GA3 but not in GA4. However, you can still pass such information about an event in GA4. You just don’t use the ‘category-action-label-value‘ format in GA4.

#3 User properties (also known as user dimensions)

User properties are like user scoped custom dimensions of Universal Analytics. They are used to describe the attributes of your website/app users.

There are two types of user properties:

#1 Predefined user properties.

#2 Custom user properties

#3.1 Predefined user properties

These are automatically collected user properties.

You don’t need to write any special code or add a tag to collect such user properties. You also don’t need to register them in the GA4 user interface before you can use them in your reports.

Following are examples of predefined user properties:

• Age
• Country
• Gender
• Interests
• Language
• Device category etc

#3.2 Custom user properties

These are the user properties defined by you. You would need to register them in the GA4 user interface before you can use them in your reports.

Note: You can create up to 25 unique user properties per GA4 property.

To learn more about user properties, check out this article: How to create user properties in Google Analytics 4 (GA4)

Best practice for naming custom events and parameters

Use lower case for event/parameter names. And if your name has got two or more words then separate the words by an underscore.

For example:

• webinar_signups (instead of Webinar Signups)
• excel_chart_optins (instead of Excel Chart options)
• website_leads (instead of website-leads)

The following event names are reserved and cannot be used as the name of custom events:

1. ad_activeview
2. ad_click
3. ad_exposure
4. ad_impression
5. ad_query
6. adunit_exposure
7. app_clear_data
8. app_install
9. app_update
10. app_remove
11. error
12. first_open
13. first_visit
14. in_app_purchase
15. notification_dismiss
16. notification_foreground
17. notification_open
18. notification_receive
19. os_update
20. screen_view
21. session_start
22. user_engagement

The following parameter name is reserved and cannot be used as names for custom parameters:

• firebase_conversion

Your parameter names can not begin with:

1. google_
2. ga_
3. firebase_

Best practice for naming user properties

The following user property names are reserved and cannot be used as the names for custom user properties:

1. first_open_time
2. first_visit_time
3. last_deep_link_referrer
4. user_id
5. first_open_after_install

Your user properties names can not begin with

1. google_
2. ga_
3. firebase_

How to send an event along with a parameter to GA4

Let’s track clicks on a button as event and then send this custom event to GA4 via GTM. Let’s also pass the button caption as additional information, along with the event via a parameter.

This exercise will help you gain a better understanding of the concept of events and parameters.

Follow the steps mentioned in this article: How to set up Custom Events in GA4 via Google Tag Manager

Measurement Protocol and event parameters

The measurement protocol is a set of rules which your application must follow in order to send event data directly to the Google Analytics servers from any device/system which can be connected to the internet.

The basic understanding of how measurement protocol works can help you greatly in understanding event parameters.

You can find more details about measurement protocol from here: Introduction to Measurement Protocol in Google Analytics 4 (GA4) – Version 2

Frequently asked questions about Event parameters in Google Analytics 4 (GA4)