Hi all,
Since the subject of the “proximity app” that is meant to keep us all safe was raised, I have been struggling to understand the reasoning behind its application. Now, with a few recent weeks of practice, we are all well-acquainted with the good old “stay 1.5 metres away from everyone” rule. No probs, and I see it in action wherever I go, and we practice it too. But here’s where they lose me with this app:-
From what I read, it uses Bluetooth to know when someone else’s phone is within a 1.5m radius of you. It then monitors you/their proximity and alerts something (someone/some website/their phone/your phone) once you have remained in that proximity for FIFTEEN MINUTES…… :o
Say wha? We can’t stay within 1.5metres at a Supermarket for more than a few seconds, but “something” will raise an alert if we’re together for 15 minutes – Wow! How cool…. or…. how stupid…. How can this really DO anything of value? If someone coughs on me when close by, can’t I get it in just a few seconds? So what’s the use of a 15 minute measurement? Really….
Or am I missing something here? Please help if you know the answer.
A few extra thoughts. IF 15 minutes is really the new “watch out you’ll get it” parameter, how does it work if you stay close by for 10 minutes, then move away for a minute or two, then move back together again for another 10? Does it accumulate the total time, or does it say “No, you weren’t together for a 15 minute span.” It had BETTER BE the former (cumulative) – or it is useless, surely. I mean, you stand next to someone for 15 mins, you’re gunna shuffle around, or if walking together, at some point you are bound to step outside 1.5 meters at some point then resume your closeness.
Or does this REALLY only work when you are sitting? Let’s say, a barber giving you a haircut or a style – the hairdresser is BOUND to move away from you at times to go and get stuff. So, it had better be cumulative – but does anyone KNOW? ‘cos right now, I have this app firmly in the arena of “Don’t bother”. what about you?
Benny
Are you talking about the Covidsafe app?
If you are – from what I understand it works by alerting you if someone you have been in proximity with in the last however many days has tested positive to Covid-19. This is not a real time thing as anyone knowingly with covid is expected to self isolate. However if someone is using the app then comes down with Covid-19, their data can be uploaded/used (done at the request of a health professional) and that will alert all the people you have been in proximity with in the last two weeks that they were in proximity with someone who has since tested positive to Covid-19, and those people who have been in proximity should get tested. You are correct in that it tracks using bluetooth. This is how I understand it to work.Hi Azalia,
Thanks for having a go. I agree with all you say re the app. However, the tenet of my question is around that “15 minutes” and its validity. I don’t see why they chose 15 minutes as the “key timeframe” to measure. It just seems wildly wrong, even inadequate, to me (see my whole spiel re my concerns).
e.g. I wouldn’t want to be within 1.5 metres of anyone for even a few seconds right now (save for my family) – just in case. :)
Benny
Okay, I’m not a conspiracy theorist, but I have to admit to some serious reservations about downloading an untested app, without sufficient privacy laws in place now, and with a government that is making policy up on the run who is bribing us to download the app with promises of ‘we will let you all out of lockdown sooner if you have it.’
This government isn’t high in trust stakes after the bushfire response. Trust needs to be earned, not given.
– Steve
Steve McKnight | PropertyInvesting.com Pty Ltd | CEO
https://www.propertyinvesting.comSuccess comes from doing things differently
e.g. I wouldn’t want to be within 1.5 metres of anyone for even a few seconds right now (save for my family) – just in case. :)
My understanding is that is more of an IT question.
Things are being “polled” at regular intervals. If your phone is uploading / downloading continuously non-stop every second, then a) your phone will probably have a battery life of 2-3 hours and b) your download limit will be used up before you know it.
So to compensate for it, the app is probably designed to take a balance. So that the amount of data being sent from your phone to the database is sufficient enough so it can be considered as “reasonably accurate” (of course, if you purposely try to break it, then that is a different story… but we are talking about average responsible citizens who are able to apply common sense), but at the same time not destroy your phone battery and / or your monthly data limit.
I didn’t make this app so I can’t comment on exactly what algorithm is applied but based on my IT knowledge, it would be something like this:
1. At time 0, your phone sends data
2. At time 0 + X minutes, someone walks past you and breaches the 1.5m threshold. Your phone registers this but probably won’t raise an alert yet
3. At time 0 + 2*X minutes, if that someone is no longer within 1.5m, then do nothing. Otherwise flag it but give it the benefit of doubt that this particular person may have walked away and come within 1.5m again but is leaving soon. Flag as suspicious but don’t raise alert yet
4. At time 0 + 3*X minutes, that person is still detected to be within 1.5m, then raise alert.
Something like that.
Hi Steven,
Thank you – that is the bit I was missing – that makes sense to me, and now the 15 minutes sounds more reasonable. Obviously then, the onus remains on us to keep our distance as was always the case. The app was never going to keep us safe – more like an insurance policy that kicks in when an affected “someone” has been near us for longer than a chance passing by. And of course, it is only if/when one of us (them or me) becomes infected that the other is notified to get checked.
I’m cool with that – and thanks again. Case closed :)
Benny
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