Compare time series from data sources: JHU, Risklayer, RKI, ZEIT ONLINE, ...

[jgehrcke]

With the current state of tooling in this repo we're now approaching a state where it's easy to compare time series obtained from different data sources, and where it will be easy to do so continuously do so (with automation). A simple plot showing the four time series named in the title will reveal a lot about the relationship, differences, and commonalities between the data sources.

[jgehrcke]

A preliminary plot that I've just prepared:

Some quick observations:

• Qualitatively, all sources show the same picture.
• "Meldeverzug" is real and significant (data is coming in to the RKI with a multi-day, sometimes even multi-week delay).
• Only the RKI properly accounts for Meldeverzug (re-writing history every day, adding individual data points to their time series based on the original "Meldedatum", which is probably the date where the local Gesundheitsamt learns about a case).
• Quantitatively, when looking at a day that is more than two days in the past, the non-RKI sources keep record of a case that is by 5.000 to 10.000 lower than what the RKI tracks for that day.