What are our COVID-19 Key Performance Indicators? As a *general* rule, a good KPI is one that is not only meaningful, but can go both up and down. If it can only go one direction, then it is likely to be what is known as a vanity metric. An example is the cumulative death count graph. It can only go up. We generally want to avoid using vanity metrics to inform decision-making, since they’re not good at providing feedback on the impact of our decisions. Instead, here is one graph I like to track. It shows the US’s daily new deaths. Each day, we can have more new deaths or less new deaths than the previous day. It grows exponentially when we do nothing. So we can use this graph to assess whether our efforts have been effective. Fewer deaths than the previous day are good. More deaths than the previous day are bad. Weaker exponential growth would also be a good sign, but it’s not as easy to spot.
It has a two week lag, so while the media is sounding the alarm bells over 16,000+ cumulative deaths (and rightfully so), many of these deaths were unfortunately locked in weeks ago due to our activities weeks ago. However, in the past two days, the daily number of new deaths has gone down day after day. So that’s a good sign, if this trend keeps up. Maybe I should wait a few more days to see if this trend continues.
One thing to note though is that due to this being a graph showing all US deaths, it’s possible that this is just the result of a state with many cases like New York clamping down hard. And so states with orders of magnitude fewer cases may still be on a steep exponential growth trajectory and this graph wouldn’t show that. Since their numbers are smaller, their exponentially growing numbers wouldn’t move this needle yet. We’d have to see this graph at the state level for each state to assess how individual states are doing.