Summary / TL:DR: This article will show you some details on how the automatic winner selection works in Blueshift.

In order for the automatic winner selection feature to work there must be at least 20 users in the segment otherwise Blueshift may select all the users to be in the holdout group so the campaign would be unable to determine the winning experiment based on the chosen metric since there would have been zero sends to the test audience.

Wrap up

You should now have a better understanding how the automatic winner selection works in Blueshift.