The contact-tracing app, accuracy?

Here you go:

https://covid19.nhs.uk/risk-scoring-algorithm.html

And if you want to get technical:

https://developer.apple.com/documentation/exposurenotification/enexposureconfiguration

Ok, that doesn’t really answer my question, lots about how it assesses how close you were, next to nothing concrete about frequency or duration of contact and how that impacts the risk calculation. Just a vague disconnected sentence about 3.6 minutes randomly inserted in the middle.

I guess the question is why you feel the need to do that (turning it off and on)? Do you have security concerns, tracking, or just general distrust? I mean its totally up to you no one can stop you turning off and on just intrigued.

No concerns like that at all; I do it to avoid having to charge my phone as often. I switch WiFi off, and mobile data, and location unless I need them. Bit like turning the telly off when I go to bed.

Given that most of my leisure time is spent in isolated countryside, alone, there’s no point keeping things running.

She works in a school, and all staff are expected to install it I think.

I’d be tipping off the school, frankly. First positive case just reported at my lads college, teacher who was warned by track and trace about a social contact, absolutely vital that staff do all they can to identify if they are putting others at risk.

People really seem to be looking to find fault with this app.

It certainly answers your hypothetical situation.

Near under 2m
Medium 2-4m
Far 4+m (ignored by algorithm)

Duration averaged over every 3.6 minutes for scoring into High, Medium and Low risk.

Finally multiplied by infectiousness of individual you came into contact with.

Aggregated over a day to calculate your risk score.

So someone walking past you isn’t even going to move the needle.

So someone walking past you isn’t even going to move the needle.

Glad someone else read it like that!

Again, I see no reason to have the app running in my house.
I switch it on when I go into places where it may provide information which will be useful, but leave it off when it won’t.

Today I have been mostly walking on the moors; little point in using it.
I then wandered down into the village; little point in using it.
I sat in a bar with two friends; app switched on.
When I left, I turned it off to walk home.

The idea that switching it on and off is some kind of toil, or that I may forget is only applicable to simpletons.

The whole intention is its passive – its not something you need to remember to turn on/off; suggesting that people are simpletons because they may forget to turn it on is frankly both rude, and unrealistic – I assume you’ve never put your phone on silent and missed a call later as a result? As I’ve not been in a bar or cafe since march, on your basis I wouldn’t bother to install it – but I might stop to help someone who’s lost when I’m on a walk, or countless other scenarios where I end up in relatively close proximity to others for a period of time unpredictably, and where I wouldn’t have their contact details.

I’ve not been back through the thread so apologises if this has already been covered but has anyone had a notification of any form yet.

I had something which I didn’t read and cleared by accident. Went into the app and can’t find anything to suggest what the notification was? I downloaded on Thursday and haven’t been anywhere since apart from a very brief visit to ASDA.

Duration averaged over every 3.6 minutes for scoring into High, Medium and Low risk

What’s averaged every 3.6 minutes, sorry for being thick, the estimated distance to another phone?

I’ve not been back through the thread so apologises if this has already been covered but has anyone had a notification of any form yet.

I had something which I didn’t read and cleared by accident.

There were a few notifications from my Android phone overnight, but they disappeared 🤔 Something about it needing Bluetooth to work (but Bluetooth is always on).

suggesting that people are simpletons because they may forget to turn it on is frankly both rude, and unrealistic – I assume you’ve never put your phone on silent and missed a call later as a result?

This is me all the time. I used to turn WiFi, NFC, Bluetooth off and on to save battery. Then try to pay for something forgetting NFC is off, wondering why the Internet seems slow at home then remember WiFi is off etc. etc. So I just leave it all on now. Batteries are decent size.

What’s averaged every 3.6 minutes, sorry for being thick, the estimated distance to another phone?

I assume it estimates a distance reading every 3.6 mins, then averages the readings? e.g. sitting right next to someone for 36 minutes would be higher risk than a waiter coming up to you four times over the same 36 minutes.

I’ll use my phone the way I want to use it, thanks all the same. Given that the entry requirement to my drinking establishment is to have the app active and scan in before getting a seat, there’s no danger of me forgetting.

– but I might stop to help someone who’s lost when I’m on a walk, or countless other scenarios where I end up in relatively close proximity to others for a period of time unpredictably, and where I wouldn’t have their contact details

The point, which seems to have evaded some is to alter your behaviour; you’ve had 8 months worth of time to practice. The app isn’t magic, so actively avoid spending time in relatively close proximity to others instead of relying on some gadget.

Crikey, use it how it makes sense in your case. It sounds like you’re being pretty reasonable. At least you’ve installed and are using the app. My phone will go 2 days, roughly, between charges with everything including Bluetooth switched on anyway, so the power consumption of this app is in the noise for me.

Interestingly, out of 3 of us in our office today I’m the only one to have installed it. One older guy who’d heard it munches your battery, and the other who was worried about being required to isolate unnecessarily. They’re both smart people. It worries me a bit they haven’t looked in to it further.

The point, which seems to have evaded some is to alter your behaviour; you’ve had 8 months worth of time to practice. The app isn’t magic, so actively avoid spending time in relatively close proximity to others instead of relying on some gadget.

I have which is why I’ve not been in a pub or cafe since March. On the other hand, if I see someone in trouble on the hills, woods, or roads I’m not going to ignore them because of a theoretical covid risk.

But hey, I’m not the one calling others simpletons!

Interestingly, out of 3 of us in our office today I’m the only one to have installed it. One older guy who’d heard it munches your battery, and the other who was worried about being required to isolate unnecessarily. They’re both smart people. It worries me a bit they haven’t looked in to it further.

The thing is even in a non covid world many won’t / don’t bother to do any further reading if they did I think our gov’ would be a lot better hands. The isolation thing I think is a real concern especially for those who need to be in a place of work to do their job – especially when you got handcock saying oh if you gotta isolate you can just collect standard sick pay which wont be paying anything more than a phone bill.

For the sake of national harmony and in light of the current situation, I hereby formally withdraw my simpleton insult. I think we’re all dealing with this in our own ways; given the lack of sensible guidance it seems that’s all we can do.

I am actively avoiding any crowded places; I have developed a very low tolerance for other people but, as you have said, nor would I avoid helping.

I’m off out now and will use the app as soon as I stop.

🙂

I’ve downloaded it but struggling to get it to work? It say ‘Contact tracing is off’ but I can’t seem to turn it on. Bluetooth is on. Button at bottom saying ‘Contact tracing’ won’t flip to on (assuming on is to the left).

iPhone 7 running 14.0.1

The isolation thing I think is a real concern

I’m not saying it isn’t. Though for both of those in my office it won’t be that big a deal, and apparently it’s not a big deal for jamze’s friend either, but here we are. Again, the government has done a great job of destroying confidence and trust.

Dogbone, suggest you uninstall, reinstall.

I don’t need the app, I’ve already got decent antivirus on my phone.

Thanks Del. Now working.

Cougar, afraid so if I’m reading it correctly.
…
App tells you to isolate, get negative test, continue to isolate.

That’s insane.

App tells you to isolate, get negative test, continue to isolate.

Which I suspect is why a good few people won’t be downloading the app…

Again, I see no reason to have the app running in my house.

Your partner gets flagged as at risk by the app, because you’re not running it at home it breaks the chain between you and her so everyone you’ve been in contact with who should be notified isn’t.

I do it to avoid having to charge my phone as often.

The technology used is BLE – Bluetooth Low Energy. Lighting up your screen multiple times a day to turn the app on and off probably uses more power than if you were to just leave it on and leave your phone dark.

Does your phone battery not last the day? Is plugging it in before you go to bed far less hassle than buggering about in application settings every ten minutes? (I mean, there’s a risk you might forget, but surely only a simpleton would do that…)

App tells you to isolate, get negative test, continue to isolate.

That’s insane.

Maybe not.

Let’s say ‘Bob’ has a positive test result and the app tells the 6 people he’s been in close contact with to self-isolate. One of those contacts (let’s call him ‘Cougar’) has a a chance (let’s say 30%) of having caught coronavirus from Bob. The app tells Cougar to stay home so he doesn’t infect anyone else. If it didn’t do that, the r-value for Bob would be two (30% x 6 contacts).

The app doesn’t tell Cougar’s contacts to self-isolate. He’s only got a 30% chance of having the virus, so his contacts only have a 10% chance of being infected – so it would be too strict to get them staying home too.

We want Cougar to get tested so that if he does definitely have the virus we can tell his contacts to self-isolate.

However the test doesn’t pick up Coronavirus while it’s incubating – so Cougar’s negative test is just as likely to mean (for Cougar) that he’s still developing enough viral load to be detected as it is to mean he’s not been infected. So unfortunately for Cougar he has to stay in until the 14 days are up (if he remains symptom-free).

Good thinking. It is, I guess, all just a numbers game.

I’d be tipping off the school, frankly. First positive case just reported at my lads college, teacher who was warned by track and trace about a social contact, absolutely vital that staff do all they can to identify if they are putting others at risk.

My partner works in a school. They’ve been explicitly told that they cannot have the app running whilst at work.

meh.

Mrs C doesn’t have the app, has no interest in having the app and her lifestyle is such that she probably doesn’t need the app because she can’t catch anything from a sewing machine to which I am a widower.

I really don’t need to justify the way I use my phone to anyone so you can all kindly jeff off.

I’ve turned it on once today and now I’m home I’ve turned it off again.

I can tell you all that I’ve met 2 people for a time greater than 15 minutes all day because I’m an antisocial **** who regards most people in a less than positive light.

I’m using it in a sensible and limited way that corresponds with my lifestyle and is as effective as leaving it on all the time, without leaving it on all the time.

I really don’t need to justify the way I use my phone to anyone

No, but if you’re doing it to save battery it’s likely to be having the opposite effect. Which is rather a silly thing to do.

If you’re doing it just to be contrary then fill your boots, I couldn’t care less.

but if you’re doing it to save battery it’s likely to be having the opposite effect

As noted above, I’ve turned it on once and off once.

Much though I appreciate your concern, it’s really nothing to do with you.

It’s all getting a bit

because I’m an antisocial **** who regards most people in a less than positive light.

Evidently.

30 odd years of public service tends to leave its mark.

Anyone any idea what happens if your Employer installs this on a work phone and you already have it on your own personal phone ? i.e. you’d be running two instances of it which will see each other as contacts ?

My partner works in a school. They’ve been explicitly told that they cannot have the app running whilst at work.

Trying to work out the logic of this 🤔

Anyone any idea what happens if your Employer installs this on a work phone and you already have it on your own personal phone ? i.e. you’d be running two instances of it which will see each other as contacts ?

Well in theory if you were notified as being in contact with someone who is positive, or you tested positive and put the result into one of the phones, the other phone should notify you too.

Trying to work out the logic of this 🤔

I think it’s mostly that the head teacher is a control freak. Logic does not often feature strongly in her (many) staff mandates.

No concerns like that at all; I do it to avoid having to charge my phone as often. I switch WiFi off, and mobile data, and location unless I need them. Bit like turning the telly off when I go to bed.

My 6S battery is so bad now my phone goes on Flight Mode whenever I leave the house for more than an hour as otherwise it just drains the battery flat whilst I’m out (I assume mainly through base station handovers as I always kill all the apps when I’ve finished using them).

Getting a new battery has been on my ToDo list for some time…..

Getting a new battery has been on my ToDo list for some time…..

For the cost of it, why not upgrade to a 7? By the time you have sold your 6S and bought a decent 7 I would have said the costs would be similar and a good 7 (with, say, 90% battery health) will last much longer than a 6S with a brand new battery.

https://www.bbc.com/news/technology-54328644

Sounds like you need to get onto this lot as well lads.

So, had the App running on my phone since it was launched. Got an alert this evening saying something like I might be at risk. So you click on the alert (iPhone) and it takes you to the App. Then nothing. Literally nothing. Not when, where or for how long. So I’ve absolutely no information on which to react.

Sorry if this has been covered earlier but how completely useless. My inclination is to ignore as I have no way of quantifying the risk. I don’t expect names and mugshots but something would be helpful.

The protect.scot app now has a “Pause” facility for use if working whilst wearing full PPE, behind a perspex screen etc.

wearing full PPE, behind a perspex screen etc.

This is what’s concerning NHS staff- the app doesn’t know when you’re wearing PPE, so if I’m on ICU next to a C+Ve patient I’ll be flagged as a contact. Not sure I’ll remember to turn the app on and off for each shift…