On 21/7/20 12:16 pm, Glen Turner wrote: > I'd add that success should be measured by the system's usefulness to > contact tracers. > > Conversely, the Apple+Google model places the person holding the phone > as the "user" of the app. I'd argue that this is a US-centric view not > well suited to countries with effective public health agencies. > > BTW, I'm not sure that accuracy is an attribute needed for success. > Consider that requiring the scanning of a big QR poster upon entry to a > commercial premises isn't that accurate but would be just as as > effective for contact tracing as all the Bluetooth messing about.
The 'accuracy' thing has been critical to the success of manual contact-tracing. They haven't extended the catchment too far, and consequently they have cred, and people who they nominate as being at-risk generally take them seriously. A major problem with Bluetooth signal-strength as a proxy for proximity is that the correlation between the two can be petty poor. So, to include enough really-at-risk people in your list, you have to open out to include a lot of low-risk people as well. (Leave aside the 6-12 other problems with the whole 'put your trust in tech' approach). The QR-code-at-the-shop-entrance has similar problems, because it too is a poor proxy for proximity. It may have some application in a very small shop (extreme case: premises in which most people go to the counter and it's the shop-assistant who was the carrier), but even then the time factor can matter. We should be drawing on the distilled wisdom of the contact-tracing teams, to work out the factors that they consider - and to find out the contexts in which they fear they may have missed some people who, with hindsight, they should have prioritised for isolation and testing. -- Roger Clarke mailto:[email protected] T: +61 2 6288 6916 http://www.xamax.com.au http://www.rogerclarke.com Xamax Consultancy Pty Ltd 78 Sidaway St, Chapman ACT 2611 AUSTRALIA Visiting Professor in the Faculty of Law University of N.S.W. Visiting Professor in Computer Science Australian National University _______________________________________________ Link mailing list [email protected] http://mailman.anu.edu.au/mailman/listinfo/link
