While this data has historically been retained indefinitely, marketers must now make a decision on how long they’d like to keep User and Event data before it’s automatically deleted by Analytics’ servers.

If you take no action, the default setting is to retain User and Event data for 26 months — after which, it will be automatically deleted on a month-by-month basis.

However, you have the option to set it to:

  • 14 months
  • 26 months
  • 38 months
  • 50 months
  • Do not automatically expire

The changes will come into effect from 25th May 2018.

Which types of data will be affected?

To decide how long you should set your data retention period for, you need to understand the types of data Google will delete after the 25th May. This is what Google has to say about the type of data that will be affected:

  • Any User and Event data that is older than your retention setting will be marked for permanent deletion, and will no longer be accessible in Google Analytics.
  • Deletion will affect the use of segmentation, some custom reports and secondary dimensions when applied in date ranges older than your retention setting.
  • Reports based on aggregated data will not be affected.

So, default Google Analytics reports will not be affected.

Data for visits, conversions, traffic sources, number of sessions, bounce rate, etc. should all remain the same. However, if you are using segmentation or importing details to create custom reports for profiling or similar activities, the changes will affect you. You will no longer be able to do this with data that is older than the retention period you’ve set.

Google has been vague on exactly how the changes will affect users, so we’re unable to give you an exhaustive list. However, here are some examples of data we think might be affected:

User-ID data

If you go to Audience > Behaviour > User-ID, any data that does not say "unassigned" is likely to be deleted after the retention period.

Sampled data

Default reports — Audience Overview, for example — are not subject to sampling, but ad-hoc reports (e.g. when you modify a default report by applying a secondary dimension), Multi-Channel Funnel and Attribution reports and Flow-visualization reports that do use sampled data are likely to be affected.

User and Event data

After the data retention period has passed, User and Event data may be affected. You can identify user-based data in Analytics if the section defaults to Users as the key metric:

Event data relates to things like contact form submissions, checkout completions, and PDF downloads, and is tracked via a piece of code you add to your website. This will likely be deleted after the retention period you set.

These changes are to prevent marketers from hoarding User and Event data for no particular reason. Marketers will need to adapt and be proactive in analysing this data before it is removed. If you’re just reporting on visits, sessions, data sources etc, the changes aren’t likely to have much impact. However, marketers who use custom reports for profiling will need to pay closer attention to this.

Setting your Google Analytics data retention period

The length of time you decide to retain this data is up to you, however, we recommend that you don’t keep the data indefinitely.

The GDPR doesn’t specify minimum or maximum periods for retaining personal data. It says:

Personal data processed for any purpose or purposes shall not be kept for longer than is necessary for that purpose or those purposes.

So you’ll need to consider the purpose of keeping this data and how long it is necessary to keep it for to carry out.

Remember, you’ll only be losing access to this data after the data retention period that you’ve set has passed. Think about the trends you are tracking in Analytics, and whether the data used is likely to be affected, then set a data retention period that is long enough for you to continue to report in this way.