How can sampling be identified in a GA4 exploration?

Definition: GA4 sampling is the use of part of the events in an exploration query to estimate results for the full dataset. Google identifies sampled results through the exploration's data quality icon and the information shown by its tooltip.

Key facts

• Google's data sampling documentation says sampling can occur when the events used by an exploration exceed the property's quota.
• In Explorations documentation, Google says an exploration may use sampled data when more than 10 million events belong to a particular exploration query.
• A sampled result shows the percentage of data used in the data quality icon, according to the Google Analytics sampling guide.
• The event-level limit is 10 million events for standard properties and up to 1 billion events for Google Analytics 360 properties, the same guide states.
• Google says the exploration icon changes from green to yellow when sampling or data thresholds apply, and its tooltip gives information about the exploration data.

What should you look for in the exploration?

As of 17 October 2026, Google's Explorations documentation says the icon in the right corner changes from green to yellow when an exploration is subject to sampling or data thresholds. A tooltip then displays information about the data. The separate 360 documentation describes a red or yellow icon as sampled and a green icon as unsampled, so the tooltip is the useful place to inspect the reason and the percentage.

Explore
Data quality
Tooltip: percentage of data used and data status

The icon can also reflect privacy-related data thresholds. Google says that demographic information or data provided by Google signals can cause data to be filtered in Explorations and Reports. A yellow icon therefore indicates that the query needs inspection, while the tooltip distinguishes the documented data conditions.

Which event quotas matter for referral analysis?

Google's sampling guide defines the quota limit for event-level queries as 10 million events for standard Google Analytics properties and up to 1 billion events for Google Analytics 360 properties. It says that, when the events used to create an exploration exceed the property's quota, Analytics uses part of the data and scales the result to represent the full dataset.

For a detailed referral exploration, inspect the data quality icon after setting the date range and the referral dimensions or filters you need. The rule applies to the events used by that particular exploration query, so a source breakdown can have a different status from a broader view. Google also warns that filtering large datasets by country can result in sampling in Explore even when expanded data requests are used. Its explanation refers to datasets exceeding 100 million events and recommends reducing the report date range or using another analysis method to minimize sampling.

What changes for a Google Analytics 360 property?

The sampling guide says a 360 property has an initial default of 100 million events per query. When more accuracy is required, it directs users to the data quality icon in Explore and the “more detailed results” option. This is a higher sampling limit, so the icon remains the first check for the result currently displayed.

For a sampled 360 exploration, Google's unsampled explorations documentation says to open Data quality and select Request unsampled results. Unsampled data is available only for Google Analytics 360, only when the current results are sampled, and only for supported techniques. Each 360 GA4 property has 20,000 unsampled-query tokens per day and each query has a 5,000-token limit; the tokens are shared by all users and the quota resets at midnight Pacific time.

How should a result be recorded?

Record the exploration date range, referral dimensions and filters, property type, icon status, tooltip percentage, and whether the result was standard or unsampled. Google says standard explorations may be sampled or unsampled depending on the amount of data in the query. An explicitly unsampled 360 result is a static, read-only snapshot, and its results tab automatically expires 50 days after the request.

Related terms

• GA4 traffic acquisition
• How do I build a session segment for AI traffic in GA4 Explorations?
• Why is older AI referral data missing from GA4 Explorations?
• AI referral traffic

FAQ

Does a yellow icon always mean sampling?

Google says a yellow icon can appear when an exploration is subject to sampling or data thresholds. Open the tooltip to inspect the information associated with the result.

Can a standard GA4 property request unsampled exploration results?

No. Google's unsampled exploration documentation limits that request to Google Analytics 360, and the current exploration must already be sampled.

Why can a 360 exploration still show sampled data?

Google documents an initial default of 100 million events per 360 query. The data quality icon provides access to “more detailed results”, while the separate unsampled workflow applies when the query would return more than 1 billion events.

Sources

1. Google Analytics Help, "About data sampling", undated
2. Google Analytics Help, "Get started with Explorations", undated
3. Google Analytics Help, "[GA4] Unsampled explorations for Google Analytics 360", undated

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