>Because dead bodies tend to behave characteristically, are inconvenient both directly and via surviving relations, and present a smaller testing target (about 1% of total cases) as well as representing a full course-of-illness endpoint, these data should be generally more reliable and cross-regionally consistent than confirmed cases.
Are you accounting for healthcare system overload? The case fatality rate in northern Italy is probably going to be very different than in Japan for example.
First, the relevant comparison is the relative reliability of deaths vs. confirmed cases data.
That clarified: overloaded healthcare would probably exacerbate this. Dead bodies don't require medical treatment, though registration as a COVID casualty requires post mortem testing. Live infecteds might well be turned away from facilities, choose not to seek treatment, or expire before receiving it. All of which contributes to case undercounts.
The difference in overall CFR would likely be at best a modest multiple of best-case treatment -- admissions are stil only a fairly small fraction (4-20% figures that I've seen, lowest in Iceland) of total infecteds.
At 1% mortality with 10,000 dead, Italy would have had 1 million cases two weeks ago. The current confirmed total is 92,000, an undercount by a factor of 10, even discounting the time lag. We might assume Italy's CFR is higher than elsewhere, but pick even fairly high values and testing still seems higghly inadequate. Two weeks ago, total confirmed cases were 21,000. A fifty-percent mortality is not credible.
TL;DR: Deaths are a vastly more reliable, though still approximate and undercounted metric, than confirmed cases.
Something feels wrong here. But I am just a clueless programmer and armchair expert. A thing I see is that you shouldn't use CFR this way because the CFR is only known after the end of the pandemic. Hoever I agree with the conclusion that the number of cases is not reliable, but not with the way you deduct this.
If I'm understanding you, that's largely the point I'm making. Italy's apparent anomolously high CFR is all but certainly a measurement artefact and not a clinical actual ground truth.
The deviation itself, though, points to insufficient monitoring rather than exceptional lethality. You cannot just look at apparent CFR and without question.
Are you accounting for healthcare system overload? The case fatality rate in northern Italy is probably going to be very different than in Japan for example.