Understanding Google Analytics 4: Key Data Changes for Source Tracking

Published: 10/5/2023

Overview

This article addresses a vital analysis detail when using Google Analytics 4 (GA4). This change in how GA4 acts compared to the previous versions can risk marketers making decisions that could negatively impact their spend allocation.

GA4 Data Change

One of the most critical metrics marketers track is what specific sources are sending traffic to your website. GA4 has changed what data is displayed and how it is collected in the most common report marketers use.

“First User by Source” vs. “Session Source”

When logging into GA4, most people go to the “Acquisition -> Overview” page to review their traffic source numbers. However, that report and the “Acquisition -> User Acquisition” page default to the “First User by Source” field, not “Session Source”.

The “First User by Source” field, unless the individual tracking is a blogger or app owner, can be problematic as a primary analysis for most marketers. Per Google, “these are users who landed on your website or app for the first time through an organic search (e.g., through Google Search).”

The graphic above illustrates Sam’s two visits to an organization’s site and the source for each visit. Let’s walk through Sam’s visits to show how the GA4 report would capture the data:

1. On the 1st of last month, Sam searched for the organization’s brand on Google and clicked the brand name on an ad. Sam went to the organization’s site and signed up for the newsletter.
2. Imagine that the organization then sent Sam an email on the 26th of the month, which interested Sam and sent them back to the site, where they made a purchase.
3. The GA4 default report, when reviewed, would show that Sam’s source is from Google’s paid ad, even though there was a delay between Sam’s visits of more than three weeks.

When to Use “First User by Source” Field

While this view is helpful to a blogger, app owner, or newsletter creator who only wants to see where new views come from, it can be not easy to those with complex multi-touch campaigns or mature marketing teams managing various channels.

Alembic’s Use of “Session Source” Field

To avoid this overly aggressive credit to previous traffic history, Alembic is using the “Session Source” field as the metric and dimension pulled from GA4 into our platform. (This data can be found in GA4 by navigating to “Acquisition -> Traffic Acquisition”) Using this field avoids the risk of inconsistent user counts across GA versions and provides a more accurate look into an organization’s data.

Defining a Session

For reference, in GA4 a session initiates when a user either opens an app in the foreground or views a page or screen and no session is currently active (e.g., their previous session has timed out). There is no limit to how long a session can last, but a session ends (or times out) after 30 minutes of inactivity.

How can Alembic help?

Working with Alembic can address these various source tracking issues by ingesting your 1st party visit data and coupling it with your sales/lead data. We can see the halo effect and dependencies of your campaigns. Find what marketing truly is driving performance for your business.