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dznlead55 karma

Can you please give us a breakdown on various contact tracing technologies (Bluetooth, GPS, ultrasound) - and there respective pros and cons? I'd like to know about privacy, accuracy, battery impact, etc.

Thank you!

dznlead16 karma

Thanks for your reply!

re: Bluetooth - while I agree that it is the most widely adopted solution, I think the biggest problem is that Bluetooth has been shown to have an effective range of 90 feet (~30 meters), and there is no correlation between relative signal strength indications and distance. Researchers from MIT and IBM have even discussed that using RSSI as a proxy for distance is effectively just guesswork. Any other users in the range of a Bluetooth scan from my device will be picked up as interacting with me - even if they were across the street in another house or apartment. Or, even more shockingly, if I was in Restaurant A, and someone next door in Restaurant B had the same app, it would say we interacted. This is unfortunately not a very accurate solution, and will lead to massive over-reporting, which renders the technology less useful, in my opinion. The signal-to-noise ratio on applications that use this technology is not valuable enough to warrant sustained use.

re: GPS - I'd actually argue that GPS is even worse than Bluetooth, as it's altitude agnostic, and would classify anyone in an entire apartment building as having interacted, even if that building had 40 stories. In urban environments, it's been shown that GPS accuracy can have variance of upwards of 100 feet, if not 200 feet, due to signal obfuscation from skyscrapers. In my humble opinion, any solutions that rely on GPS should be disregarded, as they are not only privacy invasive (they say who is sick, and where), but they are also incredibly inaccurate, specifically in the urban areas where contact tracing solutions are so desperately needed.

re: Ultrasound - I agree, there has not been a massive roll out yet for Ultrasonic based contact tracing apps. But I think this technology is our dark night, and it needs to be adopted very soon. It's the only technology I'm aware of that is actually capable of accurately gauging distance between people, using acoustic physics to gauge precise distances. https://novid.org should be the primary candidate.

I'd love to hear your thoughts on my points. Thank you again!