Today I came up with an idea to use existing data in a new way, and I'll start with my findings right away: European countries are not detecting the vast majority of COVID-19 cases. The actual amount of cases in Europe is likely 3 to 7 times higher. I'll explain why I think so.

What I did is calculate the current ratios for South Korea, Italy, France and Spain, in three categories:

1. Confirmed cases (=people infected with COVID-19) / people on intensive care
2. People on intensive care with COVID / people who died due to COVID
3. Confirmed cases / COVID deaths

When visualizing the data in a 3D radar chart, it's easy to notice how the South Korean ratios which includes the amount of confirmed cases is way off, compared to Italy, France and Spain. The ratio of COVID-19 patients on intensive care/deaths is similar in all countries though.

Now, it's quite easy to detect COVID-19 persons who have died or are on intensive care and submit them to a labtest.

It's much harder however to detect all mild COVID-19 cases.

This too implies the reported number of deaths and ICU are more likely to be correct than the number of cases.

Finally, both data and logics point me to one and the same observation. To get the same ratios as South Korea (assuming the virus is the same in Europe and Korea), the number of confirmed cases in Italy, Spain, France have to be THREE to SEVEN times higher than currently reported.

For the record, there is a very logical explanation why South Korea has a high number of confirmed cases compared to Southern Europe.

They test A LOT. They have drive-in/drive-through screening centers where you get diagnosed without leaving your car and get the result by text message.

In total S. Korea tested 191692 people as of March 10. The effect of their huge testing system is also found by studying the breakdown to age of confirmed COVID-19 cases. Compared to China, Korea has way more confirmed cases among young persons, which are more likely mild cases.