This is also one of the recommendations our paper https://arxiv.org/abs/2005.11283 which looks at joint distributions of in- and out-degrees. (They reference this paper.) If you want to find people with high out-degree, you should trace contacts backwards. - Cris

On Aug 12, 2020, at 12:21 PM, Michael Kleber <michael.kleber@gmail.com> wrote:

Following up on our discussion in April/May about the non-uniformity in COVID transmission event sizes -- i.e. the average reproduction number R_e doing a bad job of explaining dynamics because the distribution is highly skewed.

Japan's COVID contact tracing (and now Massachusetts's also) are using *retrospective* rather than prospective tracing. In brief, when someone tests positive, the standard prospective approach is to try to track down the people they might have given it to -- their children in the transmission tree. In retrospective tracing, you instead look for their *siblings* in the transmission tree: other people who might have become infected the same time they did.

In a regime where lots of transmission happens at "superspreading events", you get a lot of benefit from this change -- even after you pay the latency cost of trying to find people one infection-generation later in their disease cycle. Here's some analysis of the dynamics:

Twitter thread: https://twitter.com/AdamJKucharski/status/1293472353758871552 Preprint: https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fwww.medrxiv.org%2fconten...

--Michael

-- Forewarned is worth an octopus in the bush. _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fmailman.xmission.com%2fc...

Cris Moore moore@santafe.edu The way to right wrongs is to turn the light of truth upon them. — Ida B. Wells-Barnett