Google Analytics is a powerful tool that helps businesses understand and analyze user interactions on their websites and apps. One important aspect of Google Analytics is attribution, which determines the role of each touchpoint in driving conversions and assigns credit for sales to specific interactions in conversion paths. In this comprehensive guide, we will explore how attribution works in Google Analytics 4 (GA4) and discuss the various models and scopes available.
In the past, Universal Analytics attributed the entire credit for conversions to the last click. This model, known as the last non-direct click model, only considered clicks and did not count direct visits. Other attribution models were available in the Multi-Channel Funnels (MCF) reports section. However, GA4 offers a wider range of attribution models depending on the scope of the report, whether it is the user acquisition source, session source, or event source.
GA4 introduces three scopes for source dimensions: user, session, and event. These scopes are the most important and fundamental changes in the attribution area. The term “source” is used broadly to indicate the origin of a visit, such as channel grouping, source, medium, ad content, campaign, ad group, keyword, or search term.
In 2024, Google modified the terminology in Analytics, replacing the term “conversions” with “key events.” The term “conversion” in Google Analytics is now reserved for Google Ads conversions imported from Google Ads.
The session source refers to the source that started a session, such as a social media referral or organic search result. If a direct visit starts a session, the session source will be attributed to the source of the previous session. A direct visit occurs when Analytics does not know where the user came from because the click does not pass the referrer, gclid, or UTM parameter. The session source will be direct only if Analytics cannot see any other source of visit for the given user within the lookback window, which is typically 90 days in GA4.
It’s important to note that a session in Google Analytics is not the same as a browser session. A session in GA4 begins when a user visits the website or app and ends after a specified period of inactivity, usually 30 minutes. Closing the browser window does not end the session unless the browser deletes cookies and browser data. If a visit from a new source occurs during a session, a new session will not start, and the source of the current session will remain unchanged. However, GA4 records the source of this visit, and event-scope attribution reports take into account all sources of all sessions.
The first user source is a new concept in GA4 and indicates where the user came from for the first time. This attribute is important for understanding customer acquisition cost vs. lifetime value. The first user source is attributed using the last non-direct click model and remains unchanged unless the tracking of the user is lost, such as when the user does not visit the website for a period longer than the Analytics cookie expiration date.
Event scope attribution is another important aspect of GA4. Events have replaced sessions as the foundation of data collection and reporting in GA4. The attribution model for events is set in the property’s Attribution Settings. There are several pre-defined models to choose from, and the default model is data-driven, which can be changed retroactively.
The attribution model set in the property settings applies to all reports in the property. There are several attribution models to choose from, but they all do not assign value to direct visits unless there is no other choice. The Ads-preferred models assign the entire value of key events to Google Ads interactions if they occur in the funnel. It’s important to note that changes to the attribution model settings are retroactive and apply to historical data.
The lookback window in GA4 determines how far back in time a touchpoint is eligible for attribution credit. The default lookback window is 90 days, but it can be changed to 60 or 30 days. The lookback window for the first user source has a separate setting, typically 30 days, and it determines how far back in time GA4 looks for the source of the first visit.
Google Analytics 4 uses a different data model than Universal Analytics, and changes to the lookback window only apply to interactions still within the window. For example, if the lookback window is increased from 30 to 90 days, the key events will not immediately be reported in the new window. It will be reflected in the reports after 60 days from the date of change.
The cookie expiration and data retention periods are important considerations in GA4. The GA4 cookie has a standard expiration time of 24 months, but it can be changed to a period between one hour and 25 months. Subsequent visits may renew this time limit. However, data retention in GA4 is set by default to only two months, and it’s recommended to change this setting to 14 months. After this time, Google deletes user-level data from Analytics servers.
Exporting conversions from GA4 to Google Ads is a common practice, and GA4 offers flexible options for conversion import. Conversions can be imported using the attribution model selected in the Google Ads conversion settings. It’s also possible to choose which channels are eligible to receive conversion credit for web conversions shared with Google Ads. This allows businesses to align their GA4 conversion export with their Google Ads attribution settings.
GA4 offers various reports and visualizations for attribution analysis. The attribution paths report provides valuable insights into the days to key event and number of interactions for specific paths. The report also includes bar graphs that visualize how channels are attributed value in the selected attribution model.
It’s important to note that GA4 reports can include both tracked data and modeled data. Modeled data uses extrapolations and mathematical modeling to fill in missing data for users who have not given consent to tracking or are not logged into Google services. This blended data provides a more complete picture of the user’s journey and improves attribution accuracy.
While Google Analytics 4 introduces several changes and updates to attribution, it’s important to remember that it is designed to provide trends and support decision-making rather than record events with 100% precision. The complexity of the processes involved may result in discrepancies between different reports, but as GA4 continues to improve its algorithms, these discrepancies are expected to become less significant over time.
In conclusion, understanding attribution in Google Analytics 4 is crucial for businesses looking to analyze user interactions and optimize their marketing efforts. The comprehensive guide provided here covers the various aspects of GA4 attribution, including models, scopes, lookback windows, cookie expiration, data retention, conversion export to Google Ads, and the use of modeled and blended data. By utilizing the power of GA4 attribution, businesses can gain valuable insights into their customer journey and make informed decisions to drive conversions.
