Tracking opens is not a good metric nowadays since most email apps open emails automatically, activating tracking pixels. Custom tracking domains works. I'd say that meeting booking conversion rate takes the cake on key metrics to measure performance.
Even CTR (click through rates) can be iffy.
Top 2 metrics to measure your campaign effectiveness:
- 1.
# of booked meetings with your ICP's / # of emails sent
- 2.
$ of Revenue Generated or # of deals opened / # of emails sent