You may have seen the infinity symbol (∞) in some of your True Impact cards when measuring campaign performance against a control group:
You are seeing the infinity symbol since no one in the Control group has performed the event. Therefore, we can't calculate the effectiveness against that Control group.
True Impact works by automatically comparing each of your message creatives against a Control group of users. If there are no occurrences in the control group, we cannot calculate lift and instead show the infinity symbol.