[gbhn]

I think the theory is "there are few enough we didn't notice."

There's other weird effects going on -- some countries that look really really similar have vastly different experiences with the virus. (Canonical example is DR and Haiti, although the situation is dynamic enough no-one knows if that'll last.)

My takeaway from the difficulty in measuring this thing is that there is pretty high variance in transmission. Some carriers spread it REALLY well. Some carriers spread it poorly. With a lot of variance it matters a ton to figure out what is the deal with high-transmission situations. My take so far is we have some clues but no certainty. (Seems to spread in public transit and healthcare environments more rapidly, but slower than you'd expect in schools and prisons.)

It'd clearly be a gigantic win in terms of intervention policy to understand this better, and we simply cannot do that without extensive contact tracing so we know what's going on. They're doing a pretty good job of this in China, HK, Taiwan, South Korea. As nearly as I can tell we're doing a dismally poor job in the US and Europe.

You read papers that have diagrams of restaurant tables and bus seating charts from China. In the US it's hard to get stats on aggregate nursing home vs non-nursing home fatality rates. Maybe it takes some time for these papers to come out, but I don't see evidence that high-quality pre-pub contact tracing data is being relied on to develop policy responses.