[GA4] Detailed Explanation of Attribution: How to Set It Up and Utilize It

February 4, 2025

Attribution in GA4 is a method of analyzing the contribution of each channel leading up to key events. In this article, we will provide a detailed explanation of how attribution works, how to configure settings such as the lookback window, and how to effectively utilize attribution reports.

What is Attribution?

Attribution is a method of analyzing the contribution of each channel leading up to a key event (conversion). In GA4, you can assess the extent to which each channel influenced a user’s journey from visiting the website to reaching a key event.

In web marketing, attribution analysis is an effective way to accurately understand the effectiveness of advertising and SEO efforts. Since users often visit a website through multiple channels, it is important to evaluate not only the last channel they interacted with but also the first touchpoint and any intermediary touchpoints along the way.

Types of Attribution Models

GA4 offers several attribution models, each of which assigns credit for key events differently. The way contribution is distributed among various touchpoints depends on the specific model used.

Data-Driven

Data-Driven Attribution (DDA) is a model that utilizes machine learning to calculate the optimal contribution based on user behavior data. It is the default attribution model in GA4, analyzing past key event data to optimally assess the impact of each channel.

The advantage of Data-Driven Attribution is that it enables a fair evaluation based on actual data. This model reflects the true contribution of each channel. The default attribution model in GA4 is this Data-Driven model.

A user's site visit channel	Model evaluation
Social > Organic Search > Paid Search	Machine learning is used to assign contribution to all channels.

Last Click for Paid and Organic Channels

Last-click attribution is a model that assigns 100% of the credit for a key event to the last channel the user clicked before converting. While this model is simple and easy to understand, it does not take into account the impact of initial or intermediate touchpoints, which can lead to an inaccurate evaluation of the overall effectiveness of advertising efforts.

Additionally, if the last channel is "No Referrer" (Direct), the model ignores the direct visit and attributes the credit to the last known channel instead.

A user's site visit channel	Model evaluation
Social > Organic Search > Paid Search	Assign all attribution to Paid Search
Display > Social > Paid Search > Email	Assign all attribution to Email
Social > Organic Search > No Referrer (Direct)	Assign all attribution to Organic Search
No Referrer (Direct)	Assign all attribution to No Referrer (Direct)

Google's Paid Channel Last Click Attribution

Google's Paid Channel Last Click Attribution is a model that assigns 100% of the credit for a key event to the last-clicked Google Ads channel. This attribution model is specifically designed for evaluating Google Ads performance.

If there is no traffic coming from Google Ads, the attribution will follow the same channel evaluation as the Paid and Organic Channels Last Click model.

User's Site Visit Channel	Model Evaluation

Social > Organic Search > Paid Search

All attribution assigned to Paid Search

Display > Social > Paid Search > Email

All attribution assigned to Email

Social > Organic Search > No Referrer (Direct)

All attribution assigned to Organic Search

No Referrer (Direct)

All attribution assigned to No Referrer (Direct)

Measurement Period in Attribution Analysis

In attribution analysis, key events that occur within a specified period are associated with the preceding touchpoints. In GA4, this period is defined by a setting called the "lookback window," which determines how many days prior to the key event should be considered for attribution. The way the lookback window is configured significantly impacts the evaluation of each channel's contribution.

For example, consider the following user journey:

January 1: Arrived via paid search
January 20: Arrived via social media
February 10: Arrived via organic search
April 25: Arrived via display advertising and triggered the key event

If the measurement period is set to 90 days, GA4 will evaluate interactions that occurred within the 90 days leading up to April 25, when the key event occurred. In this case, the paid search visit on January 1 falls outside the 90-day window and will not be considered in the attribution analysis. Instead, the remaining channels will be evaluated.

How to Set Up Attribution in GA4

In this section, we will explain in detail how to set up attribution in the GA4 admin panel. Attribution is configured by default, so if you want to change the attribution model or the lookback window, you can do so by following the steps below.

First, navigate to the GA4 admin menu and select Attribution Settings.

(Quote:GA4)

Next, select the attribution model you want to use. When you change the model, it will be applied retroactively to past data as well.

(Quote:GA4)

You can also change the channels to which attribution is assigned. If you select Google's paid channels, the attribution will be assigned only to Google Ads channels.

(Quote:GA4)

The lookback window for key events can also be modified. By default, it is set to the recommended value. Unlike model changes, modifications to the lookback window will only apply from the moment they are changed onward. Please note that past data will not be affected.

(Quote:GA4)

That concludes the explanation of the attribution settings screen. Next, we will introduce practical ways to utilize attribution.

How to Utilize Attribution

Let's take a closer look at the contribution of each channel. In GA4, navigate to the advertising menu and select "Attribution Paths."

Attribution Path

(Quote:GA4)

Next, configure the key events to be tracked and the level of granularity for the channels being analyzed.

(Quote:GA4)

Key Event: Select the key event you want to focus on.
Channel: Choose the level of granularity for Default Channel Group, Source, Medium, or Campaign.
Model: Select the attribution model to be used in the report.

Once the settings are complete, review the report to analyze the contribution of each channel.