How we calculate it

<aside> 💡 Fatality rate = number of deaths / total cases

</aside>

We know what you're thinking. Why aren't we using "closed cases (= death + recoveries)" rather than "total cases"?

Why we're not using "closed cases"

1. The recovery data provided by the governments is not as reliable as the death data. Some governments don't even provide regular data about recoveries at all. If we estimated the fatality rate by giving the deaths and recoveries equal importance and credibility, we would almost certainly hugely overestimate the fatality rate. That's not a desirable outcome.
2. "Total cases" is only the number of cases that were officially reported. The actual total number of cases might be 2, 10 or 50 times higher. By definition, cases that aren't reported (mild symptoms, populations that aren't at risk...) have a much higher likelihood of ending in a recovery than a death. We need to keep in mind that the sample we have at our disposal might not be representative of the whole.
3. If anything, the app's goal is to inform and reassure, objectively. We're dealing with imperfect data, and we believe that it would be a dangerous mistake to inflate the fatality rate by ignoring point 1 and 2 above.

Use with caution

We strongly discourage comparing the deadliness of the coronavirus with other diseases using the fatality rate we show on coronavirus.app. The obvious drawback of our approach is that it factors cases that haven't had an outcome yet. On the other hand, the fatality rate of other diseases you'll see online is calculated exclusively with closed cases. So don't compare them.

Then, why are we even displaying the fatality rate?

The fatality rate, as we calculate it, is helpful to compare the deadliness of the virus across regions. And because we're not factoring the recoveries at all in the calculation of our fatality rate, it doesn't carry additional bias due to the differences in the way governments report that specific data point.