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GA4 Guide Chapter 11: Optimizing Acquisition Channels

Lachlan Brown
Digital Marketing Director
Sep 13, 2022

One of the most valuable features of GA4 is its ability to provide actionable data and insights to optimize traffic acquisition channels such as paid search and display. In this chapter, we’ll cover some fundamental reporting and integration features and more advanced use cases, including audience creation and cross-channel analytics using Google Cloud.



This chapter contains more details on a subject introduced in Chapter 1, namely optimizing how people find your website to help you acquire new and better visitors.

Acquisition reports let you determine where your new and returning users are coming from, i.e., from which referring channels, sources, etc., and other important metrics. This may include traffic referral channels such as paid and organic Google searches.

  • Acquisition overview summarizes your acquisition data, such as new vs. returning, channel performance, and Google Ads.
  • The User acquisition report indicates how various traffic channels perform as the touchpoint through which users reached your site in the chosen date range
  • Traffic acquisition also shows Channel performance but is specific to that session and not necessarily the first time you saw these visitors—a major difference from Universal Analytics
  • Acquisition reports are populated from three external methods:
  • Integrate with GMP ads platform (Google Ads, DV360, SA360)
  • Use auto-tagging from a platform such as Google Ads or CM360
  • Manually tag tracking URLs with UTM parameters (e.g., utm_medium / utm_source)
Chapter 11 Overview


The acquisition overview report summarizes your acquisition data to help you understand where your traffic comes from.

These reports are highly customizable, but, by default, the following reports are available:

  • Overview: Includes important acquisition metrics with a time series chart trend line for each metric over the date range you’ve chosen
  • Users in the last 30 minutes: shows current activity using real-time reporting data. The card shows the number of users, grouped by first user default Channel grouping, on your site or app in the last 30 minutes. Something new to GA4 is that dimensions with the preface “First User” indicate a channel or referral source that first drove that user to the website.
  • The New users by First user default channel grouping: Summarizes the information in the User acquisition report.
    Sessions by Session Google Ads campaign:
  • The Sessions by Session Google Ads campaign card summarizes the information in the Google Ads campaign report.


The User acquisition report shows where new users come from (for active users in the chosen date range, located in the top right corner). Say, for example, you acquire a user in January. If the user is active in April, you’ll see the user in the April report with data about how you first acquired the user in January.

By default, the report is grouped by the First user default channel grouping dimension. However, you can use the drop-down in the table to change the dimension that organizes the table (and the two visualizations that are shown). The “First user” prefix in “First user default channel grouping” indicates that the default channel grouping applies to new users. Learn more about the traffic-source dimension scopes.


The Traffic acquisition report shows you where new sessions come from, including both new and returning users. The traffic-source dimensions in this report include the prefix “Session.”

By default, the report is grouped by the Session default channel grouping dimension, but, again, you can change the dimension that organizes the table (and the two visualizations that are shown) using the drop-down in the table. The “Session” prefix in “Session default channel grouping” indicates that the Google Ads campaign applies to new sessions.


You can populate the reports with more detailed acquisition data by integrating Analytics with the following ad platforms and then using the auto-tagging feature available with the integrations. Alternatively, you can manually tag the destination URLs in your ads with UTM parameters.

  • Google Ads
  • Display & Video 360
  • Search Ads 360


The Advertising snapshot report allows you to quickly check your business metrics and then dig deeper into the areas you want to explore. The summary cards in this overview report include data from June 14, 2021, onwards. Each card addresses a single question about your business.

There are three summary cards in this snapshot:

  • Conversions by Default channel grouping: Learn which channels in the Default channel grouping drove the most conversions. Note: This card uses the reporting attribution model (set in Admin > Attribution settings) to attribute conversions to specific channels.
  • Conversion paths: See your top conversion paths and how many conversions they drove during your selected date range.
  • Model comparison: For each channel, see how credit shifts under different attribution models. Use the drop-down menus at the top of the card to select other attribution models to compare.


User-scoped dimensions
User-scoped dimensions show you where your new users are coming from. These dimensions always include the prefix “First user,” as in the First user source dimension (which shows you the most common sources for new users). The value assigned to each user-scoped dimension remains the same as users return to your website or app.

Session-scoped dimensions
Session-scoped dimensions show you where both new and returning users are coming from when they start new sessions. These dimensions always include the prefix “Session,” as in the Session source dimension (which shows you the most common sources for new sessions)

Event-scoped dimensions
Event-scoped dimensions help you attribute credit for a conversion event that a user triggered. Event-scoped dimensions don’t include a prefix, as in Source or Medium. The source and medium for non-conversion events are “(not set).”


Attribution in Google Analytics 4 properties provides enhanced attribution features—such as a revamped Conversion paths report—and new attribution features—such as property-level attribution modeling—that provide deeper insights and more actionability than ever.

For user-scoped and session-scoped dimensions, Analytics uses the cross-channel last click attribution model. User-scoped and session-scoped dimensions are unaffected by changes to the attribution model.

For event-scoped dimensions, Analytics uses the attribution model you select, but, by default, Analytics uses the data-driven attribution model. All reports with event-scoped traffic dimensions reflect the attribution model you select.


Customers may do several searches and click several of your ads before making a purchase or completing another valuable action on your website. Typically, all credit for the conversion is given to the last ad customers clicked. But was it solely that ad that made them decide to convert? What about the other ads they clicked on before it?

Attribution is the act of assigning credit for conversions to different ads, clicks, and factors along a user’s path to completing a conversion. An attribution model can be a rule, a set of rules, or a data-driven algorithm that determines how credit for conversions is assigned to touchpoints on conversion paths.

There are three types of attribution models available in the Attribution reports in Google Analytics 4 properties: cross-channel rules-based models, an Ads-preferred rules-based model, and data-driven attribution.

To find the Attribution reports, click Advertising on the left. Under Attribution, click either Model comparison or Conversion paths.


Data-driven: Data-driven attribution distributes credit for the conversion based on data for each conversion event. It’s different from the other models because it uses your account’s data to calculate the actual contribution of each click interaction. Therefore, each Data-driven model is specific to each advertiser and each conversion event.

How data-driven attribution works
Attribution uses machine learning algorithms to evaluate both converting and non-converting paths. The resulting Data-driven model learns how different touchpoints impact conversion outcomes. The model incorporates factors such as time from conversion, device type, number of ad interactions, the order of ad exposure, and the type of creative assets. Using a counterfactual approach, the model contrasts what happened with what could have occurred to determine which touchpoints are most likely to drive conversions. The model attributes conversion credit to these touchpoints based on this likelihood.


Cross-channel last click: Ignores direct traffic and attributes 100% of the conversion value to the last channel the customer clicked through (or engaged view through for YouTube) before converting.

Cross-channel first click: Gives all credit for the conversion to the first channel that a customer clicked (or engaged view through for YouTube and other Google Display) before converting.

Cross-channel linear: Distributes the credit for the conversion equally across all the channels a customer clicked (or engaged view through for YouTube) before converting.

Cross-channel position-based: Attributes 40% credit to the first and last interaction, and the remaining 20% credit is distributed evenly to the middle interactions.

Cross-channel time decay: Gives more credit to the touchpoints that happened closer in time to the conversion. Credit is distributed using a seven-day half-life. In other words, a click eight days before a conversion gets half as much credit as a click one day before a conversion.


Ads-preferred last click: Attributes 100% of the conversion value to the last Google Ads channel that the customer clicked through before converting. If there is no Google Ads click in the path, the attribution model falls back to Cross-channel last click.  


Users with the Editor role on the property can now select an attribution model and lookback window at the property level to apply to a number of reports. To access this setting, go to Admin > Attribution Settings.



Google Ads
When you link your Google Analytics 4 property to your Google Ads account, you can:

  • See your Google Ads campaigns in the Acquisition overview report
  • Access new Google Ads dimensions in the User acquisition report
  • Import Analytics conversions into your Google Ads account
  • Enhance your Google Ads remarketing with Analytics audience data
  • See your Google Ads campaigns in the Advertising workspace, including the Attribution reports

When you link your Google Analytics 4 property to your Display & Video 360 advertiser, you get the following benefits:

  • Analytics exports audiences and conversions to Display & Video 360.
  • Your Display & Video 360 advertiser appears as a traffic source in your Analytics cross-channel reports.
  • Display & Video 360 campaign and cost data is imported to Analytics.

Audience export
To export audiences from Analytics:

  • Activate Google signals in the Analytics property
  • Enable Personalized Advertising in the GA property settings

With Google signals activated and Personalized Advertising enabled in the link settings, audiences are automatically exported to Display & Video 360.

Audiences that contain demographics or interests data will not be exported.

When you export audiences, they appear under All Audiences in the linked Display & Video 360 advertiser. You can use the audiences as-is for targeting or combine them with other audiences. You can also perform analysis on them.

Conversion export
When Analytics exports conversions, it uses the cross-channel last click attribution model. You can use those conversions for custom bidding in Display & Video 360.

When you link your Google Analytics 4 property to your Search Ads 360 advertiser, you get the following benefits:

  • Analytics exports audiences to Search Ads 360 (Available only if you have upgraded to the new Search Ads 360 experience. If you have enabled continuous audience sharing in your Search Ads 360 manager account, these audiences will be shared with all existing and future Google Ads sub-accounts.)
  • Analytics exports conversions to Search Ads 360
  • Search Ads 360 campaign and cost data is imported to Analytics
  • Analytics app- and site-engagement metrics are available in Search Ads 360 reports (Available only if you have upgraded to the new Search Ads 360 experience.)

Audience export
To export audiences from Analytics:

  • Activate Google signals in the Analytics property
  • Enable Personalized Advertising in the link settings

Audiences that contain demographics or interests data will not be exported.

When you export audiences via the continuous audience sharing feature, they appear in the linked Search Ads 360 manager account and in the related Google Ads serving accounts. You can use the audiences as-is for targeting or combine them with other audiences. You can also perform analysis on them.

Conversion export
Analytics exports conversions that use the cross-channel last click attribution model. You can use the conversions for reporting.

To export conversions, you need to turn on the Enable Campaign Attribution setting when you configure the link.



The GA4 BigQuery export can be the foundational dataset when joined with other data sources such as Google Ads, Campaign Manager 360 (CM360), and Display Video 360 (DV360), as well as first-party data such as CRM and customer service. Then, it can be used to generate holistic insights across marketing channels and create Advanced audience segmentation for Performance Marketing.

Create custom audiences
You can combine first-party data such as predicted CLV (customer lifetime value) and combine that with the GA4 BigQuery export data tables, or you can process the GA4 export data by itself using a GCP ML modeling service like BigQuery ML.

The resulting CLV index values can be pushed back into GA4 via the Measurement Protocol, which will then allow you to build and publish remarketing audiences that combine both onsite behavior, such as visiting the site within a certain recency or key content, with CLV values to further improve the performance of your remarketing efforts.

Another example of a sophisticated remarketing audience using GA4 data is one (or several) made up of users determined to have a high propensity to buy.

You can also use Google Cloud to build custom integrations to push the data back into platforms of your choice. For example, you can run scheduled queries to generate audience lists with your Analytics data and then push the data back with API calls, including the Google Analytics Measurement Protocol. You could also use Cloud Functions to trigger the data push to Google Ads or CM360/DV360 after a new segment is ready in Cloud Storage.

Create marketing mix modeling to optimize marketing spend
Google Cloud streamlines pulling data across multiple sources, including GMP advertising platforms Google Analytics and first-party data. Machine learning tools like Big Query ML and Vertex AI can be used to easily build AI models which generate comprehensive insights to help inform and optimize all of your marketing channels.

BigQuery can be used to provide the following three levers: prediction, automation, and optimization. It is the lens and warehouse that provides a single location for customer relationship management, advertising, and website information & provides a full life cycle view of every business and individual that interacts with a company’s product and/or services.

Chapter 11 Advanced


One of the most important roles for a web analytics platform such as Google Analytics is to understand how users are finding your website, what keeps them returning, and how to capitalize on this existing and potential customer engagement.

GA4 streamlines this reporting into two distinct categories: User Acquisition (how visitors come to your site for the first time) and Traffic Acquisition (what channels or campaigns drive individual sessions). The reports containing this data use a last click attribution model.

Many of the other reports in GA4 use an attribution model that is set at the property level by an admin, which is set by default to data-driven attribution. This paints the most accurate picture of which traffic drivers should get credit for visitors, leads, and sales, in particular those occurring prior to the last click in a multi-touch user conversion journey.

GA4 also integrates seamlessly across the GMP, including Google Ads, SA/DV/CM360. This provides a holistic look at advertising performance by including these acquisition channels, along with other sources such as organic search and social media, in the attribution model. Additionally, you can create sophisticated audiences for targeted marketing via the GMP and via Ad Manager for publishers.

Finally, GA4 can be used for advanced marketing and customer analytics when combining the GA4 BigQuery export with customer/first-party data & third-party data and utilizing the many tools available in the Google Cloud Platform, including built-in machine learning models.

Lachlan Brown
Digital Marketing Director

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