In short. Older AI referral events can fall outside GA4 retention and disappear from Explorations while standard aggregated reports retain their totals.
Definition: Event data retention controls how long Google Analytics 4 (GA4) keeps event-level data. Older AI referral visits can disappear from Explorations when they fall outside the retention period, while their totals remain available in standard aggregated reports.
Key facts
As of 17 October 2026, Google documents the following reporting scope and settings:
- Google's data retention documentation states that retention affects Explorations and funnel reports; standard aggregated reports, including comparisons, remain unaffected.
- Google's Explorations guide specifies a default retention period of 2 months.
- Google's Traffic acquisition report documentation lists Session source and Session source / medium as available dimensions for examining acquisition.
What happens to older events?
Google's retention documentation lists 2 months and 14 months as the event retention choices for standard properties. An exploration requesting dates beyond the configured period excludes the older data.
Expired data is deleted during a monthly process. Increasing retention applies to previously collected data that survives deletion. Extending the setting cannot recover events already deleted.
Where is the retention setting?
Google's Explorations guide gives this administration path:
Admin > Data collection and modification > Data Retention
The guide places the exploration's date selector at the top of the Variables panel. Selecting a custom interval fixes the exploration to those dates; a saved preset interval moves with time when the exploration is reopened.
Google's retention documentation requires the Editor role to change the setting. The Event data retention control selects the period, and Save applies the selection.
Where can older referral totals remain visible?
Google's Traffic acquisition guide gives this report path:
Reports > Acquisition > Traffic acquisition
The report covers acquisition for both new and returning users. Session source identifies where traffic originates; Session source / medium pairs that source with the acquisition method. Its Sessions metric counts sessions beginning on the website or app.
For an assistant source already recorded in the property, the table's search field narrows the report to that source. Google's retention documentation exempts standard aggregated reports from the retention setting, including reports using secondary dimensions or comparisons.
Related terms
- GA4 traffic acquisition
- AI referral traffic
- How do I build a session segment for AI traffic in GA4 Explorations?
FAQ
Can I restore deleted events by selecting 14 months?
Google's retention documentation says an increase applies to collected data that has not already been deleted. Deleted events remain unavailable.
Can a saved exploration keep showing the same dates?
Yes. Google's Explorations guide says a saved custom date range stays fixed. The underlying data remains subject to the property's retention period.
Sources
- Google Analytics Help, "Data retention", undated
- Google Analytics Help, "Get started with Explorations", undated
- Google Analytics Help, "[GA4] Traffic acquisition report", undated
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