I’ve never liked the User Acquisition report in Google Analytics. When I want to see where users come from, I skip this report and go directly to Traffic Acquisition.

The User Acquisition report is all about user-scoped dimensions— which I find confusing. This confusion makes it hard to fully understand how to use this report effectively. Chances are, I’m not the only one, so let’s take a closer look at GA4’s user-scoped dimensions and see how they can be put to good use.

When you open this report and expand the list of available dimensions, you’ll see quite a few options:

Take “First-user default channel group” as an example. If we understand how this dimension works, we can apply the same logic to the other dimensions in this group.

The “First-user default channel group” is a user-scoped dimension (one of three scopes in total) that reports on the channels through which users first arrive at your site (the word “first” is important here). Channels are rule-based definitions of your website’s traffic sources (learn more about channel group definitions).

For example, these are some of the channels that can drive traffic to the XYZ website:

Setting the Scene

Let’s look at an example:

Justin, Brandon, Alex, and Hugo each visited the XYZ website for the first time at different points in January. 

Their first visits were attributed to different channels, representing how they arrived:

• Justin came via a Facebook ad; his visit was attributed to Paid Social.
• Brandon also arrived through a Facebook ad; his visit is also attributed to Paid Social.
• Alex found the website by clicking a Google Ads link; his visit is attributed to Paid Search.
• Hugo arrived through Organic Search.

GA4’s user-scoped dimension, the First-user default channel group, captures each user’s original channel, preserving this “first touch” information no matter how many times they return or which channels they use in the future.

In February, each of these users revisited the site once and made a purchase. 

Here’s how they arrived at the site for their purchase:

• Justin found the website through an Organic Search on Google.
• Brandon also arrived through Organic Search.
• Alex clicked a link on another website, classified as Referral.
• Hugo came via a Facebook ad, attributed to Paid Social.

Today is March 1, and Tam, the marketing manager at XYZ, is reviewing the User Acquisition report. The First-user default channel group is set as the primary dimension, and Tam selected the date range February 1 - 29.

Bucketing

In February, a total of four people visited the site. Google Analytics creates a list of all First-user default channel group dimension values. 

These have not changed since January, even though users arrived through different traffic sources in February:

• Paid Social
• Paid Social
• Paid Search
• Organic Search

Google Analytics then creates a bucket for each unique channel value:

• Paid Social
• Paid Search
• Organic Search

Each user is then placed into the correct bucket:

• Paid Social: Justin and Brandon
• Paid Search: Alex
• Organic Search: Hugo

The breakdown of the First-user default channel group by Total Users would look like this:

• Paid Social: 2
• Paid Search: 1
• Organic Search: 1

Since each user converted during their second visit, their number of E-commerce Purchases would be the same:

• Paid Social: 2
• Paid Search: 1
• Organic Search: 1

Notice that credit is given to the original traffic source attributed to each user from their January visit. Although users visited the site through different marketing initiatives in February, these later touchpoints don’t receive credit in this report.

Understanding the Data

From this example, the Paid Social default channel group comes out on top. In a real-world scenario, if Paid Social ranks as the top First-user default channel group for e-commerce purchases in February and this trend continues in March and April, Tam might prioritize introducing users to the site through Paid Social over Paid Search. This would be because users initially introduced via Paid Social consistently show a higher likelihood of converting than those introduced through Paid Search.

In practice, the User Acquisition report is useful for identifying which traffic sources work best for awareness campaigns—but that’s about it.