On-call: one person on watch, rung first

An On-call page per project, in the Operations group: a rotation — one day or one week each, in the chosen order —, stand-ins for holidays, the upcoming shifts in your timezone. When an incident stays unacknowledged past the set delay, the person on call receives an email naming them; escalation to the whole team remains the second ring. And responsiveness over thirty days: median time to acknowledgement, incidents closed without answer.