Contact tracing works but on its own isn't sufficient.

After of our dissertation and direct experience, we still believe that contact tracing apps, on smartphones and through BLE, could help in slowing down Covid-19 -and future virures- spreading. Despite being not conclusive on their own, they are still a very promising approach in our simulation.

- High effectiveness requires high adoption
However, the effectiveness of the apps supported by governments must raise dramatically, otherwise citizen's trust would drop soon, and won’t trigger the required collaboration level, mandatory to succeed.

- Current effectiveness is too low
The effectiveness of currently deployed solutions, seems to be as low as 10.40%: it means only ~10 infectious notified on 100 really infectious citizens, in our rough calculation.

- Next challenges
To improve the effectiveness all the developers should openly discuss technical challenges, and adoption strategies (effectiveness also depends on the count of collaborative citizens enrolled with the app). We have few ideas to share about.

Suggestions to all our colleagues:

1- Mass adoption of digital systems is never a matter of imperatives, but a matter of long, faceted, unpredictable and multi-disciplinary negotiations. While we don’t see adoption strategy talks in the news feeds, we have a process to suggest, to build a resilient one, based on design techniques out of abundant literature.

2- Introduce a threshold for the probability of being infected and alerted, we named it the “risk index”, so that authorities' responses can be sorted by priority, and thousands less people would be forced to quarantine without a real need.

3- Apple and Google are working on some of the most impacting technical issues: they are the only one that can change the limitations imposed by their operating systems. We trust and admire their good will and ability, but we spotted a few potential weaknesses that could be mitigated by:

3.a) shard keys in broadcasted lists, while changing the IDs encryption flow to allow it;

3.b) scrambling the intensity of the radio signals (not too much, to preserve reliability)