Hello, Jennifer. Thank you for your questions.
My name is Ivan Maltsev. I am Deliverability Expert at Microsoft Dynamics 365 for Marketing.
The numbers are being calculated based on actual sending statistics. We have automatic alert set up that is being triggered if actual rate of bounced emails reaching the limit of 8%. It is a calculated as a ratio of bounced emails compared to the amount of actually sent emails.
We send an email to the "Company Administrator" role email address with the notification that contains the bounce rate percentage, and some recommendations on how to resolve this issue and link to our email deliverability best practices documentation webpage.
Hope this information helps you. If you have any additional questions - please do not hesitate to ask. I will be glad to answer.
