If your site or app has many millions of pageviews or screen views per month, you might consider configuring your tracking code to sample your data. For information on how to do this, follow the instructions in the Developer Guide for your specific environment:
- Website tracking: Universal Analytics (if using gtag.js) or Classic Analytics (if using ga.js)
The changes you need to make to your web pages depend on which tracking code you’re using. See if you have Classic Analytics (ga.js) or Universal Analytics (gtag.js).
- Mobile app tracking: Android apps or iOS apps.
By sampling the hits for your site or app, you get reliable report results while staying within the hit limits for your account (10M hits/month for Standard; 2B hits/month for 360).
When you implement data-collection sampling, hits are discarded on the client side (your site or app) and are never collected or processed by Analytics. As a result, you cannot recover those discarded hits by using the 360 unsampled reports. Also, unlike session sampling, Analytics does not extrapolate report results based on the data-collection sample rate. That said, an added benefit of data-collection sampling is that report response times may be faster with less data in the account.
Data-collection sampling occurs consistently across users. Once a user has been selected for data collection, Analytics collects data for all of that user’s sessions.
For mobile applications, downloads of the application that have been selected for data collection send all data to Analytics, while other instances of the application do not send any data.
Even if the data for your site is not sampled when it is collected, certain reports encounter other types of sampling, including session sampling and dimension-value aggregation, based on the nature of the query. Learn more about how Analytics samples data for ad-hoc reports.