[melling]

How effective are the apps for contact tracing?

Getting people to use them is work but there should be a huge savings in human effort.

[zhdc1]

From a quick look at what's been published so far, they appear to be very effective if they have a high enough adoption rate and if people self quarantine after contact.

This is ancedotal, but the benefit of having a live person, working in an official capacity, doing the contact tracing, is that it gives definitive weight to the decision to quarantine and get tested.