Yesterday the Italian government released the analysis that motivated the very mild release of the lockdown. This is an impressive analysis and essentially takes into account all the points I raised last week; the population is divided into age groups with different susceptibility and transmission rate, it is done at the regional level and takes into account an incredible amount of information. Really fantastic work.
However, all the predictions rely on one crucial data: the CFR in Lombardia which is 0.657%. This is incredibly pessimistic and is caused by the fact that the Lombardia health system was overwhelmed. The same value for the rest of Italy would be much lower, about half. In Sweden, the CFR is 0.3% and in other countries is even lower. If a value of 0.35% had been used, the estimate of critical cases would have also been (more or less) halved and the rate of spread would have also been reduced considering that twice as many people would have been categorised as immune.
So why was the CFR of Lombardia used for the whole of Italy? The model is run on each regional independently, so why not use the regional CFR too? I am sure the results would have been significantly different and the Italians would have been less upset.