Hey, thanks for your question. The tool keeps track of declaration and resolution times by watching when the status is changed. It also lets you manually specify when the incident really started, and when it actually ended. We can use this data to measure a few things, and watching how this changes over time helps us figure out if we're getting better or worse, on average. We want to be careful what we incentivise by default, and we're actively working on this area. The data is going to be available for people to build their own visualisations (in Grafana).
I'd be very interested to hear your thoughts too?