Forum search & shortcuts

The contact-tracing...
 

[Closed] The contact-tracing app, accuracy?

Posts: 4209
Free Member
 

Monday from 11:45 to midnight. It doesn’t take that long to drink a cup of coffee

There's no way to sign out of a venue. The app just signs you out at midnight. Seems daft to me, why not let you sign out when you leave?


 
Posted : 04/10/2020 6:57 pm
Posts: 4209
Free Member
 

Android go to settings, then Google to find the list of scans

I found that page, it says "This shows requests made by apps to check for potential exposure…" I don't know what that means, apps on my phone making a request to the Google interface, or apps on other phones making a request to mine? It's showing 'requests' when the phone's been in the house with no other phones near it.


 
Posted : 04/10/2020 7:15 pm
Posts: 7874
Full Member
 

Scottish app. If it throws a self isolate message will that person get a phone call?


 
Posted : 05/10/2020 9:43 am
 poly
Posts: 9167
Free Member
 

Scottish app. If it throws a self isolate message will that person get a phone call?

No, they don't have your phone number - you will get a notification on your phone, but not a call.

Of course if the person who exposed you knows they had contact with you and your contact details, or there are venue/event contact details, you may get both.


 
Posted : 05/10/2020 10:23 am
Posts: 7874
Full Member
 

Bugger that's true.

If the app has a "last contact" date I assume that that's the last time the two phones interacted.


 
Posted : 05/10/2020 10:32 am
Posts: 835
Free Member
 

@Greybeard

Android go to settings, then Google to find the list of scans

I found that page, it says “This shows requests made by apps to check for potential exposure…” I don’t know what that means, apps on my phone making a request to the Google interface, or apps on other phones making a request to mine? It’s showing ‘requests’ when the phone’s been in the house with no other phones near it.

It's your phone making a request to the Google Interface. There's nowhere to see where your phone has shared a contact with another phone.

The app (broadly) works by periodically generating a unique id and sharing that with other phones running the app. So your phone ends up with a list of the unique ids of people you've been in contact with; and a list of the unique ids you've generated to share with other people.

If someone tests positive then the unique ids they've generated are uploaded to the NHS servers - so the NHS have a list of IDs from everyone who has tested positive.

Your phone every so often downloads this entire list and checks whether any of the other people's IDs it has stored match any in this list. The page you're looking at shows when your phone did this.

There are refinements around what the phone does when it gets a match around signal strength and contact duration (which your phone stores); and around how long IDs are kept for (10 days after a positive test maybe).


 
Posted : 05/10/2020 10:52 am
Posts: 4209
Free Member
 

Thanks, sl200. The list isn't really useful information, then, apart from knowing that it's working. Where there are several entries with the same time, it must be just trying to download the list but the phone didn't have a connection.


 
Posted : 05/10/2020 11:57 am
Posts: 7874
Full Member
 

So after panic about isolation, the missus giving me evils about my mysterious contact and the unpleasantness of a test. I eventually get through to track and trace folk in Scotland to be told. Unless we phone you just ignore the isolation message. We'll.thats dandy for me but there many folk who would be down a day's pay (or even a fortnight) because they followed the instructions. So do I follow app instructions or Steve from track and trace?


 
Posted : 05/10/2020 4:42 pm
Posts: 1893
Full Member
 

I’ve had the app running all day since the day of launch. This morning I opened the app to surprisingly find out I have to self isolate for ‘another 8 days’? Yet a no point was I informed that I need to self isolate at all.

@chipsngravy I've just had this explained to me by someone who had the same thing.

It's 14 days from when you were in contact with the person who's tested positive. But it might take 6 days for that positive test, so you are asked to isolate for the remaining time. Think that makes sense 🤔 Which is why we need quicker testing.


 
Posted : 07/10/2020 5:47 pm
Posts: 835
Free Member
 

Unless we phone you just ignore the isolation message.

That's very bad advice. The app is a de-centralised system. Track and Trace Scotland have no idea whether the app has detected you've been in contact with someone, and can't use info from the app to work out whether to call you. There is no point at all running the app if you ignore the isolation message.


 
Posted : 07/10/2020 6:22 pm
Posts: 7874
Full Member
 

That’s very bad advice

Yes bad advice. NHS liaison with council has confirmed it.
Although the app is a blunt tool also. I haven't been near an infected person. There's only been one locally in 10 days and I know who it is I also know I don't know them socially and have not been in close contact.


 
Posted : 07/10/2020 10:19 pm
Posts: 7874
Full Member
 

Teachers now being told to switch the app off.


 
Posted : 08/10/2020 11:00 pm
Posts: 39747
Free Member
 

BBC News - 'App thought I'd catch Covid through neighbour's floor'
https://www.bbc.co.uk/news/uk-scotland-54418278

Well that's interesting.

This week's lottery numbers are......


 
Posted : 08/10/2020 11:16 pm
Posts: 1442
Free Member
 

Having read the article on the bbc site I checked the Bluetooth on my phone and there is a JBL flip2 ‘not connected’ which obviously belongs to my downstairs neighbors
There will be quite a few people getting pinged in similar circumstances.


 
Posted : 09/10/2020 12:37 am
Posts: 1048
Free Member
 

Sometimes you just can't technology your way out of a problem.

https://twitter.com/rowlsmanthorpe/status/1314447905311387648


 
Posted : 09/10/2020 9:20 am
Posts: 0
Free Member
 

I think the fact the phone can see other Bluetooth devices in range isn't the issue, as the app is mesuring how far away they are from signal stregnth, not if they exist at all. So surely, if there's a floor/wall in the way it will work in your favour (the app will think they a FURTHER away as signal strength will be lower)??


 
Posted : 09/10/2020 9:36 am
Posts: 39747
Free Member
 

Did you read the beeb.

Man shielding in flat gets alert to self isolate because his upstairs neighbour has a positive test ?


 
Posted : 09/10/2020 9:46 am
Posts: 0
Free Member
 

I thought it was annonymous / you don't get told where the contact took place?!


 
Posted : 09/10/2020 9:58 am
Posts: 2882
Free Member
 

Did you read the beeb.

Man shielding in flat gets alert to self isolate because his upstairs neighbour has a positive test ?

It's not entirely unreasonable. The "victim" here has been leaving his flat and using the same communal stairwells / hand rails and communal doors as the positive patient. There has been a number of outbreaks within flats / tenements due to the communal nature of living. Even if he was shielding and not going out out, they would still have to use the communal areas to take their rubbish into the bins.


 
Posted : 09/10/2020 10:09 am
Posts: 39747
Free Member
 

Remind me again how the app works ? Isn't it looking for 10-15minute close contact ?


 
Posted : 09/10/2020 10:15 am
Posts: 33317
Full Member
 

So in two weeks, of all the responsible people who download and use the app properly - who are probably also being responsible about distancing and sanitiser etc etc - there's only been 1 link to a pub.

Given delays getting tests and then delays getting the results, I'm not exactly stunned by the headline, to be honest.


 
Posted : 09/10/2020 10:29 am
Posts: 1893
Full Member
 

I thought it was annonymous / you don’t get told where the contact took place?!

It is, but I assume he talks to his neighbour and is assuming the alert is linked - might not be.

Remind me again how the app works ? Isn’t it looking for 10-15minute close contact ?

More complex than that I think. It can be close contact for a shorter time, or repeated, shorter contacts.


 
Posted : 09/10/2020 10:32 am
Posts: 39747
Free Member
 

school teachers being told to not use the app.

so that leaves the most obvious transmission vector into my house unlinked to me.

- sounds like hospital staff and police are getting similar lines.

Ok i work from home and rarely leave the house these days - when i do i do as i always have even pre covid - minimise my contact time with others and also post covid wear my mask and sanitise wash my hands.

all of which works as both a defence against others having it - and me spreading it.

The app seems to clinging on to the fact it will catch folk who are not doing the above and who need to have it to get into the pub/Gym more so as many of our front line workers are being instructed not to use it, Its a feather in a cap but it doesnt seem like a particularly useful nor effective one if you exclude those most likely to be exposed to it

As an aside - as a teacher the wife is part of some study where shes getting anti body testing done - it doesnt change any precautions taken by the school as the testing is not proven 100% accurate but i guess it gives the government guidance data to see just how prevalent it has been in schools.


 
Posted : 09/10/2020 10:47 am
Posts: 4209
Free Member
 

there’s only been 1 link to a pub.

As I understand it, there are several independent functions in the App. Links to a venue are separate from contact notices in the App, as the contact-detecting bit of the App doesn't doesn't know where the contact was, only the relative position of two phones. The App itself doesn't identify a venue as a source of infection, that has to be done manually by the contact tracers, who only know where the infected person went by asking them after they've tested positive. Then the App is used to send a message to the people who scanned in using it.

Writing that, it seems to me that the App would be a lot more useful with less privacy protection. I know that was the original plan, but not whether the change was because the original App didn't work or because of the privacy issues. Personally, to saves live and save jobs in a pandemic, I'm happy to give up a bit of privacy; I don't go anywhere or meet anyone I shouldn't (actually I hardly go anywhere or meet anyone at the moment).


 
Posted : 09/10/2020 12:16 pm
Page 12 / 12