In Google Analytics 4 (GA4), dimensions are data attributes or characteristics that provide additional information about your website’s users and how they interact with your website.
For example, the “Country” dimension indicates where a website visitor is located. Which means you can see how many visitors came from different countries.
Or it could be the “Device Category” dimension. Which reveals which kinds of devices your visitors use to access your site.
Source / medium : The referring website/platform (e.g., Facebook) and the broader channel category that refers the visit (e.g., “email”)
Campaign / Campaign ID : The name of a marketing campaign that led to a conversion (e.g., “Spring2023_Sale”)
Google Analytics Dimensions vs. Google Analytics Metrics
Note that dimensions are not the same as metrics. Dimensions are qualitative aspects of your data.
You’ll find metrics like these under “ Reports ” > “ Life cycle ” > “ Acquisition ” > “ User Acquisition ” inside Google Analytics 4.
Why Are Google Analytics Dimensions Important?
Dimensions help you understand your data better. And help you gain insights you wouldn’t otherwise be able to.
Say you have two views on your website. One is from a 30-year-old woman from Mississippi who got to your site from X (formerly Twitter) using her desktop computer. The other is a 50-year-old man from Yishun, Singapore, who landed on your site from a Google search engine results page (SERP) using his mobile phone.
What Are the Types of Dimensions in Google Analytics 4?
Attribution: Includes all dimensions that provide information about how users arrived at your site Google Ads : Covers dimensions related to Google Ads
General : Includes general metrics that may not fit into other categories, like file information and search terms
Traffic source : Pertains to the origin of the user’s journey User-scoped : Focuses on the user’s first interaction sources and campaigns
Custom dimensions (which we’ll discuss more later) are different from predefined dimensions in that they aren’t automatically collected by Google Analytics.
How Do You View Dimensions in Google Analytics 4?
When you go to the “ Reports ” tab inside GA4, you’ll see reports categorized into broader collections like “Life cycle,” “User,” etc.
Within individual reports, the dimension appears at the top of the table on the left side. The dimension values are listed underneath.
The column names on the right side are metrics. And can be recognized by their numerical values. As you can see, metrics quantify the dimension values.
For example, let’s say the top row in your “Traffic acquisition” report shows you got 10,000 sessions from organic traffic. That same report also shows you how long users from organic search stayed on your site (average engagement time per session) and how many conversions they drove (conversions).
What Is a Primary Dimension in Google Analytics 4?
Primary dimensions are the default dimensions that a Google Analytics report is sorted by. And appear on the left-hand side at the top of tables.
You can also change the dimension for some reports by clicking the drop-down menu over the dimension name. And choosing another one.
This allows you to change how the data is displayed. So you can learn more about what interests you.
What Is a Secondary Dimension in Google Analytics 4?
While the primary dimension provides you with the starting point, a secondary dimension allows you to explore data based on what you find most valuable. And adds additional context and depth to the data storytelling.
To add a secondary dimension inside GA4’s reports, click on the ‘ + ’ sign beside the primary dimension dropdown.
You select the “Session source / medium” primary dimension to see where your traffic is coming from in the “Traffic acquisition” report. And notice that much of it is coming from Google Ads.
Then, you add the “Session campaign” secondary dimension to find out which specific campaign drove the most traffic.
What Are Custom Dimensions in Google Analytics 4?
Custom dimensions fulfill those needs by allowing each business to create dimensions that provide useful information specific to them. And they allow you to create customized reports that provide even more information.
But you don’t have to use custom dimensions. In certain cases, they might not add much value beyond what’s already provided by Google Analytics.
Understanding Custom Dimensions
It’s important to understand the relationship between all the elements that go into dimensions before creating custom dimensions.
A user represents a unique IP address visiting your website. And there are different properties that describe them (like where they live and what they do for work.
An event is a user interaction on the site. It can be a scroll, a click, a view, etc.
Every event contains parameters—bits of information that provide more context about the user or event. For example, a click event will contain parameters that provide information about the URL that was clicked, the link’s location, etc.
How to Add Custom Dimensions in Google Analytics 4
Also, keep in mind that the reporting on custom dimensions is not retroactive inside GA4. Meaning you need to set them up before you can begin analyzing the data.
It depends a bit on which type of dimension you’re creating (event-scoped, user-scoped, or item-scoped). But we’ll go over how to create an event-scoped custom dimension.
The event fires when a specific condition is met (e.g., someone filled out an information request form). And this event contains custom parameters (e.g., the form was located on a landing page).
You can add custom events and parameters through Google Tag Manager or directly in Google Analytics via “ Admin ” > “ Events .”
While the latter is convenient, it’s also limited. So, it’s usually best to use Google Tag Manager.
Get started by logging into your Google Tag Manager account. Then, you’ll need to enable the appropriate variable and configure your event.
You can learn more about this in our guide to Google Tag Manager —just make sure you select “ Google Analytics: GA4 Event ” as your tag type.
Once you’ve published your changes to start tracking the event, you can head to your Google Analytics account.
You’ll be redirected to a page where you can find all the custom dimensions registered with your property.
Dimension name: You can enter any name you want—something that resembles the parameter’s name (e.g., “custom_plugin_text”) or a descriptive one (e.g., “Custom plugin text”).
Event paramete r : Choose the parameter you want to collect the data on. If you used Google Tag Manager to set up your event, this parameter name should be the same as that one.
Best Practices for Effective Custom Dimension Implementation
Ensure They’re Relevant to Business Goals
Determine what data matters most to your business. To ensure you’re creating dimensions that are actually valuable.
For example, creating a “Membership level” custom dimension might be a good idea if you run a subscription-based business.
And you might create one called “Content format” if you have a portal with articles, videos, podcasts, and other types of content.
Apply Meaningful Property Values
If the custom dimension was “Membership level,” the values might be “bronze,” “silver,” “gold,” and “platinum.”
Do you need to add the “free” value? Not if you don’t have a free membership tier.
Avoid Dimensions with Too Many Unique Values
This is known as high cardinality and applies in the case of user IDs, session IDs, order IDs, timestamps, etc.
Unless you have a website that demands otherwise, avoid custom dimensions with high cardinality. It might mess with your reports and aggregate data under an “other” row.
Use Consistent Naming Conventions
While it won’t pose any real issue, it might become baffling and time-consuming for new users in your GA4 account.
Prevent Data Duplication at All Costs
If you create a duplicate one, it negatively affects the storage space and complicates data analysis.
Different Use Cases for Custom Dimensions
Tracking Differences Among User Types
A custom dimension focused on different categories of users can be helpful for seeing differences in how those groups interact with a site.
You can create a custom dimension based on user attributes to differentiate between them. And then use it to dig into specifics about those groups.
Seeing Which Content Format Performs Best
Custom dimensions can help you determine which content format works best for your audience: how-to articles, infographics, news updates, and op-ed pieces.
You can add a “Content format” custom dimension for this. Once registered, you can check for the custom dimension separately, and decide where to double down in the future.
Discover Your Top-Selling Seasonal Products
If you run an ecommerce site, custom dimensions can help you verify which products perform best during which seasons.
With a custom dimension like “Season,” every purchase transaction gets recorded with additional context. So, you can filter the data for the custom dimension and find the winning products.
How to Analyze Data with Custom Dimensions
You can access the custom dimension data in both existing reports and ones you create yourself.
For example, you can go to “ Reports ” > “ Life cycle ” > “ Engagement ” > “ Events .”
Click on the “ + ” icon in the table to add a custom dimension as a secondary dimension. In the drop-down menu, click the arrow next to “Custom” to see all the custom dimensions you can add to the report.
For example, if you want to see only the events where the “ad_frequency” custom dimension is set to “2,” you click the “Add filter” button beside the name of the report.
Last but not least, you can also create custom reports that use your custom dimensions via “ Explore ” > “ Free form .”
The Explorations feature of Google Analytics 4 allows you to create custom reports based on advanced data segmentation. Which is useful when there are multiple custom dimensions to deal with.
Empower Decisions with GA4 Dimensions
And with the right dimensions, your data becomes a reliable source of intelligence to bank on.
Organic Traffic Insights can help. Because it compiles all your data from Google Analytics, Google Search Console and Semrush in one place.
Just follow the Organic Traffic Insights configuration instructions to set up your project and connect your accounts. And click “ Go to Organic Traffic Insights ” in the setup wizard.
You’ll then be able to see a comprehensive report with data on your keyword rankings, traffic, conversions, and much more.
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