Germany's Corona-Warn-App was rolled out nationwide in June. A few days ago, the Robert Koch Institute provided an update on its progress, celebrating the fact that it had now been installed by around 16 million people. "A successful start that speaks for great interest and acceptance among the population," a statement from the app's developer said. Bear in mind, however, that there are 83 million Germans, and it is thought more than half of the population need to have an app before it is truly effective. "The app works" added the institute's president Prof Lothar Wieler. He went on to say that about 500 app users had tested positive for the virus and "had the opportunity to warn others via the app". But he then said: "We cannot say exactly how many people were warned, because of the decentralised approach of the app." In other words, we do not know whether the software is performing its key function. To know how well your app is performing, it is also vital to understand whether it is producing a lot of false positives or false negatives - in bald terms, whether the software is failing to alert people who have been in close contact with an infected user, and sending warnings to those who haven't. That's important to know, because studies have indicated that Bluetooth is an unreliable way to determine the distance between two people in some common situations. The Robert Koch Institute (RKI) told us it too didn't know because, once again, the log history it would need to tap into "remains with the users, encrypted on their smartphones". We wondered as a workaround whether Germany's manual contact tracers might provide RKI with a record of people who had come to their attention after being alerted by the app. No, came the answer. Local municipalities run manual contact tracing and do not share this information. RKI added that it hoped scientific tests would eventually assess the app's impact in the "medium to long term", but had yet to work out how this would be achieved. Switzerland faces the same issue. Continua con una disanima dei non-successi nei diversi stati su https://www.bbc.com/news/technology-53485569 Io non posso che ammirare l'acume dietro Google ed Apple. Sono riusciti a deployare su milioni di cellulari un framework che non solo non può funzionare, ma la cui inefficacia non può essere dimostrata per ragioni tecniche ed etiche: quanti contagi dovremmo causare in laboratorio ed in quanti scenari diversi per verificare che le previsioni di rischio sono completamente campate in aria? E, capolavoro nel capolavoro, se la gente lo attiva e qualcosa va storto, la colpa sarà dei governi, mentre se nessuno lo attiva, la colpa sarà della popolazione ignorante e malfidata. Giacomo