# How it works

## How the Covid-19 Map works

The Covid-19 Map gets their data from three different major sources:

We then combine the data, calculate their averages and display them.

Based on this data, we also calculate:

• the doubling time in an area
• the change rate
• the fatality rate
• the number of true cases (estimate)

## How those numbers are calculated

### Doubling Time • Td = Doubling Time
• C(X) = Total cases until day X

The doubling Time is the time it takes to double the amount of infected People.

### Change rate

The change rate describes the absolute change that occurred from one day to the next.

### Fatality rate

There are two ways to calculate the fatality rate depending on whether one wants to include all cases or just the number of closed cases.

The calculation based on all the cases looks like this: deaths / confirmed cases

The calculation based on the closed cases looks like this: deaths / (recovered cases + deaths)

We calculate both of those numbers and then display their average.

### Estimation of true cases • CFR = case fatality rate
• TSOD = time from symptom onset to death
• Td = Doubling Time

This calculation is based on an article by Tomas Pueyo, which you can find here. Since people do not display symptoms right away after being infected, this number is intended to give you a sense of the real number of infected people — as opposed to a number that represents data, which are a couple days old.