Google Analytics 360 collects enough data so that most custom reports you create will represent a true accounting of your content.
But if you build complicated custom reports featuring numerous dimensions or segments, you may encounter sampling of data in which reports are based on a portion of web analytics data. In such cases, you can pull an unsampled report to get a truer view of your content’s data.
Pulling an unsampled report
Step 1: Find your custom or saved report
Under the Customization tab on the left side of the screen, navigate to the custom or saved report you’d like to pull.
Step 2: Determine whether report data is being sampled
Click or mouse over the shield icon next to the report name in the upper left corner. When the shield is green, 100% of the sessions are being counted: Your report is not being sampled.
When the shield is yellow, your report might be based on sampled data. You can mouse over the shield to see the sampling rate.
Step 3: Schedule an unsampled report
To get a completely unsampled report, click on the shield, then click on the drop down box that says “Greater precision.” You will see 3 options, one of which is to schedule a downloadable unsampled report. Click this option.
Step 4: Finding your report
Once you schedule your report for download, you can find it under Customization > Unsampled Reports. It will appear here once it’s finished.