Many governments used different metrics to set and communicate their policies during different phases of the COVID-19 pandemic. To list just a few:
- The reproduction number (R).
- The incidence rate, usually per 100,000 people per week.
- The percentage of positive tests.
- The mortality, again usually per 100,000 people per week.
- The excess mortality.
- The infection fatality rate.
- Free hospital beds, as a percentage or absolute number.
- Free intensive care hospital beds.
- Free fully staffed intensive care hospital beds.
- Vaccination rate.
As a layman I can puzzle some of this out myself. Assuming an exponential growth function, the reproduction rate is simply the derivative of a normalized incidence. Hospital beds matter more at the peak of a wave, not at the start or tail. Widespread testing wasn't available early on, so tests were only used to confirm suspected cases. Later on, daily tests became possible. And so on.
Has any government attempted to explain the use of different metrics at different times to their general public in high-profile messaging rather than specialist-only webpages?