Why [UA to GA4] Automatic Property Creation is Risky for You

Why [UA to GA4] Automatic Property Creation is Risky for You

Feb 22, 2023


Since recommending opting out of automatic GA4 property creation, we’ve had questions asking what’s the problem with allowing Google to automatically create GA4 properties from existing UA properties.


Aren’t there benefits of letting Google create the GA4 property?


What are the risks of not opting-out?


Benefits of Automatically Created GA4 Properties

Automatically created properties mean you start receiving GA4 data right away.


However, if the data isn’t useful, there is no benefit.


The sole benefit of the automatically created property might be to show that thoughtful setup is necessary for useful data.


Risks of GA4 Properties Automatically Created from UA Properties

Organizations may not face all of these risks, depending on their operations.


1.Google will default existing UA events to the following mapping (see Google support article section on event mapping), resulting in event names that may not make sense.

  • UA Event action will become the GA4 Event Name
  • UA Event category, label and value will become GA4 event parameters
  • In many cases, due to the lack of UA storage fields, we crammed lots of data into UA events and then parsed the information out later into UA custom dimensions. The new GA4 “Event Name” may therefore not make sense when mapped from UA Event Action
  • GA4 Event Names have a 40 character limit, whereas UA Event Actions had a 500 byte limit, well over 100 characters.


2.Data quality degradation is highly likely.

  • Filtering in GA4 is minimal compared to UA, and needs to move into GTM. Automatic migration will not handle this.
  • Not only will data quality degrade but you may have increased risk of Privately Identifiable Information (PII) creeping into your data if GTM isn’t watching out for PII


3.Failed cross-domain and sub-domain tracking, causing user experience and marketing performance evaluation to fracture.

  • You may find yourself unable to make marketing budget decisions because you can’t evaluate what’s working and what’s not.
  • For cross-domain and sub-domain tracking to occur, websites must feed same data stream, in the same GA4 property.


4.Automatic mapping of UA goals from your UA property’s Default View to GA4 conversions.

  • If you have imported UA goals into Google Ads, all those goals regardless of whether the view is the Default View, will be migrated to GA4 conversions (see support article section on conversion mapping). This could cause your Google Ads account to behave strangely. Keep a close eye on how this affects your spend, if you do allow automatic GA4 creating and enablement.


5.Account clutter with unnecessary GA4 properties

  • Non-360 UA properties are subject to automatic GA4 property creation.
  • In UA, to deliver roll-ups, enable Search Console integration and manage sampling, websites might be purposefully double-tagged with multiple properties. Each of these properties, if unconnected and opted in for autocreation, will automatically generate a new GA4 property.


And if the above is not enough, notice in the Google support article that even Google recommends that you complete your own migration

For more on how to opt-out, read our earlier post. Remember that you might only have till the 28th of February to opt-out.


There’s not much time left to run UA and GA4 in parallel before data collection stops on July 1, 2023 for non-360 UA accounts. Aim for beginning your parallel run by April 1, so that you’ll have 3 months to get used to the data differences.


Do drop us a comment below if we can clarify anything for you.


If you have questions about completing your UA to GA4 migration or GA4 training, contact us.


By June Li | February 22, 2023