Google Signals and Reporting Identity
Google Signals is Google’s database of all its logged in users. This is great because it tracks unique users whether they log in from their phone, their work computer, their home computer, etc. It is ‘deduped’ and accurate. This is great for truly understanding actual ‘people’ in your analytics. It is also great for retargeting and audience creation.
So to get this capability in GA4 definitely, when creating your GA4 property, opt to use Signals. You should also add info about this to your Privacy Policy.
The only downside to this is that it applies what is called ‘Thresholding’ to some reports. If you see a little warning sign at the top fo your reports, when you click on it, it will state that Thresholding is being applied. This is not always ideal. Because it excludes rows with very small values.
To remove Thresholding, go to Admin, GA4 Property Settings and Reporting Identity. You have to click the ‘Show All’ link in the bottom right. Then you will see ‘Device Based.’ Select this method and save.
Review your reports. You will see Thresholding is gone. Reporting identity data is retroactive. So once you are done reviewing the reports without Thresholding, you can go back and switch back to Blended (also uses Modeling as an option to identify users – but that is another topic for another day) or Observed.
Hope this helps!