What is the acceptable level of death?

Across this whole conversation, whether about schools, family, work, sport, lockdown or whatever, all depend on getting an answer to this question.

The R-factor is one measure of this, as is the daily number of new presentations at hospital.

If you want to understand this, watch NY State Governor Andrew M. Cuomo:
https://www.youtube.com/watch?v=NwEldF5Me9Q
- if in a hurry, skip forward 14 minutes, but the whole broadcast is instructive - for us all.

Unless and until we get the answer, little progress will be made.