NPR

Mahoney wrote: ↑Sun Oct 04, 2020 10:40 am Unless you are testing at random you cannot know.

Bimbowomxn wrote: ↑Sun Oct 04, 2020 10:34 am

Rinkals wrote: ↑Sun Oct 04, 2020 10:17 am

Bimbowomxn wrote: ↑Sun Oct 04, 2020 8:36 am



Mostly false positive I imagine

Hey rinky.....

Tell is how many of those would be False positives if the false positives rate was 1%?

Biffer wrote: ↑Sun Oct 04, 2020 10:49 am This thread has fallen into a state where its mostly two idiots taking incredibly moronic positions on opposite sides of the debate.

Tichtheid wrote: ↑Sun Oct 04, 2020 11:09 am On false positives

https://www.bbc.co.uk/news/54270373

Bimbowomxn wrote: ↑Sun Oct 04, 2020 11:20 am

Tichtheid wrote: ↑Sun Oct 04, 2020 11:09 am On false positives

https://www.bbc.co.uk/news/54270373

This ignores the mass of testing on students and the young.

Tichtheid wrote: ↑Sun Oct 04, 2020 11:35 am

Bimbowomxn wrote: ↑Sun Oct 04, 2020 11:20 am

Tichtheid wrote: ↑Sun Oct 04, 2020 11:09 am On false positives

https://www.bbc.co.uk/news/54270373

This ignores the mass of testing on students and the young.

COVID-19 daily situation report COVID-19 admissions estimates in England

https://www.england.nhs.uk/statistics/w ... 01003.xlsx

Bimbowomxn wrote: ↑Sun Oct 04, 2020 10:42 am

Mahoney wrote: ↑Sun Oct 04, 2020 10:40 am Unless you are testing at random you cannot know.

I’m not looking for an exact number....

Just a rough idea.


More than or less than 1/2?

Dr Paul Birrell, a statistician at the Medical Research Council's Biostatistics Unit at the University of Cambridge, says: "The false positive rate is not well understood..

Dr Birrell says that to be certain cases really are increasing, the daily case count "should always be considered alongside other information sources, such as the hospitalisations or deaths, or the community surveys run by the ONS or REACT".

Rinkals wrote: ↑Sun Oct 04, 2020 12:02 pm

Bimbowomxn wrote: ↑Sun Oct 04, 2020 10:42 am

Mahoney wrote: ↑Sun Oct 04, 2020 10:40 am Unless you are testing at random you cannot know.

I’m not looking for an exact number....

Just a rough idea.


More than or less than 1/2?

Is Bimbo really saying that half of all test results are false positives?

My post that he has taken exception to was in response to his implication that Homer's graph was explained by the results being "mostly false positives".

If most (ie. more than half) of the testing results are unreliable, what is the point of testing at all?

Tichtheid wrote: ↑Sun Oct 04, 2020 12:12 pm The point was expressed in the BBC link,

Dr Paul Birrell, a statistician at the Medical Research Council's Biostatistics Unit at the University of Cambridge, says: "The false positive rate is not well understood..

False positives are not having a significant impact on figures, also

Dr Birrell says that to be certain cases really are increasing, the daily case count "should always be considered alongside other information sources, such as the hospitalisations or deaths, or the community surveys run by the ONS or REACT".

The figures in the NHS link show increases in hospitalisation, there is another table easily looked for which show an increase in deaths

Tichtheid wrote: ↑Sun Oct 04, 2020 12:25 pm From a very quick search Prof. Heneghan seems to be choosing his words very carefully, he says there isn’t enough evidence to declare a second wave yet (my emphasis) and he thinks a lockdown over Christmas is a better idea than doing it now.

Tichtheid wrote: ↑Sun Oct 04, 2020 12:12 pm The point was expressed in the BBC link,

Dr Paul Birrell, a statistician at the Medical Research Council's Biostatistics Unit at the University of Cambridge, says: "The false positive rate is not well understood..

False positives are not having a significant impact on figures, also

Dr Birrell says that to be certain cases really are increasing, the daily case count "should always be considered alongside other information sources, such as the hospitalisations or deaths, or the community surveys run by the ONS or REACT".

The figures in the NHS link show increases in hospitalisation, there is another table easily looked for which show an increase in deaths

Raggs wrote: ↑Sun Oct 04, 2020 1:14 pm

Tichtheid wrote: ↑Sun Oct 04, 2020 12:12 pm The point was expressed in the BBC link,

Dr Paul Birrell, a statistician at the Medical Research Council's Biostatistics Unit at the University of Cambridge, says: "The false positive rate is not well understood..

False positives are not having a significant impact on figures, also

Dr Birrell says that to be certain cases really are increasing, the daily case count "should always be considered alongside other information sources, such as the hospitalisations or deaths, or the community surveys run by the ONS or REACT".

The figures in the NHS link show increases in hospitalisation, there is another table easily looked for which show an increase in deaths

False hospitalizations no doubt...

Insane_Homer wrote: ↑Sun Oct 04, 2020 12:03 pm BOJO this morning: ‘behave fearlessly but with common sense’

Is that advice or law? Somehow I don't think arguing 'common sense' and quoting the PM is going to get you out of a £10k fine.

Tichtheid wrote: ↑Sun Oct 04, 2020 2:01 pm I've read Prof Carl Heneghan's article in the Spectator from back in July on false positives, unfortunately it seems to be based on a hypothetical statistics exercise, rather than a real-life situation

Article here https://www.spectator.co.uk/article/how ... tives-/amp


There is a rebuttal in the Huff post here, and before anyone dismisses the Huffpost, I'm not interested, try and refute the material in the article instead.

https://www.huffingtonpost.co.uk/entry/ ... vsISQNuxsS

Heneghan is particularly interested in “false positives” – those people who test positive for Covid-19 but actually aren’t infected. Health secretary Matt Hancock has said the false positive rate (FPR) for coronavirus tests is “less than 1%”.

But Heneghan has argued that due to a bit of a fluke involving some slightly complicated statistics, the proportion of positive tests that are false in the UK could be as high as 50%.

Ali Cadoo wrote: ↑Sun Oct 04, 2020 3:47 pm I’m sure this must all come as great comfort to all those dead people.

Bimbowomxn wrote: ↑Sun Oct 04, 2020 3:48 pm

Ali Cadoo wrote: ↑Sun Oct 04, 2020 3:47 pm I’m sure this must all come as great comfort to all those dead people.

,

Wonderfully signalled .

Raggs wrote: ↑Sun Oct 04, 2020 1:14 pm

Tichtheid wrote: ↑Sun Oct 04, 2020 12:12 pm The point was expressed in the BBC link,

Dr Paul Birrell, a statistician at the Medical Research Council's Biostatistics Unit at the University of Cambridge, says: "The false positive rate is not well understood..

False positives are not having a significant impact on figures, also

Dr Birrell says that to be certain cases really are increasing, the daily case count "should always be considered alongside other information sources, such as the hospitalisations or deaths, or the community surveys run by the ONS or REACT".

The figures in the NHS link show increases in hospitalisation, there is another table easily looked for which show an increase in deaths

False hospitalizations no doubt...

Ali Cadoo wrote: ↑Sun Oct 04, 2020 4:55 pm Guys - I’m reasonably confident that IF there were a way to accurately measure and record the impact of the ‘rona then some clever chap would have done it by now.

Sandstorm wrote: ↑Sun Oct 04, 2020 5:08 pm

Ali Cadoo wrote: ↑Sun Oct 04, 2020 4:55 pm Guys - I’m reasonably confident that IF there were a way to accurately measure and record the impact of the ‘rona then some clever chap would have done it by now.

I hope not. I have him on ignore.

Tichtheid wrote: ↑Sun Oct 04, 2020 4:20 pm If you click through to the British Medical Journal's site from the Huffpost article, they explain that the problem isn't with false positive results, which are minimal, it's actually with false negatives and we are all vastly underestimating the extent of the disease.

The pre-test probability is the crucial figure, and it depends on symptoms and prevalence of the disease in the patient's area as well as things like any travel etc.

If you are in a high probability group, ie around 90% you have a 99% chance of having Covid 19, but even after one negative test you still have a probability of 75% of having the disease, this falls to 47% even after two negative tests.

https://www.bmj.com/content/369/bmj.m1808

Ali Cadoo wrote: ↑Sun Oct 04, 2020 3:49 pm

Bimbowomxn wrote: ↑Sun Oct 04, 2020 3:48 pm

Ali Cadoo wrote: ↑Sun Oct 04, 2020 3:47 pm I’m sure this must all come as great comfort to all those dead people.

,

Wonderfully signalled .

How’s your ‘cunt signalling’ working out for you? Are you happy to have removed all doubt?

.OverThere wrote: ↑Sun Oct 04, 2020 4:30 pm

Raggs wrote: ↑Sun Oct 04, 2020 1:14 pm

Tichtheid wrote: ↑Sun Oct 04, 2020 12:12 pm The point was expressed in the BBC link,



False positives are not having a significant impact on figures, also



The figures in the NHS link show increases in hospitalisation, there is another table easily looked for which show an increase in deaths

False hospitalizations no doubt...

How many were hospitalised in September for normal flu? How does this compare with the 10 year average, and how does it compare with covid hospitalisations? Similarly the comparisons for deaths?

Bimbowomxn wrote: ↑Sun Oct 04, 2020 5:46 pm

Tichtheid wrote: ↑Sun Oct 04, 2020 4:20 pm If you click through to the British Medical Journal's site from the Huffpost article, they explain that the problem isn't with false positive results, which are minimal, it's actually with false negatives and we are all vastly underestimating the extent of the disease.

The pre-test probability is the crucial figure, and it depends on symptoms and prevalence of the disease in the patient's area as well as things like any travel etc.

If you are in a high probability group, ie around 90% you have a 99% chance of having Covid 19, but even after one negative test you still have a probability of 75% of having the disease, this falls to 47% even after two negative tests.

https://www.bmj.com/content/369/bmj.m1808

Yeah, Carl Heneghan is a clutz.

Bimbowomxn wrote: ↑Sun Oct 04, 2020 5:47 pm

Ali Cadoo wrote: ↑Sun Oct 04, 2020 3:49 pm

Bimbowomxn wrote: ↑Sun Oct 04, 2020 3:48 pm
,

Wonderfully signalled .

How’s your ‘cunt signalling’ working out for you? Are you happy to have removed all doubt?

No, I too am ever so caring about the dead people. I’ll ignore science I’m that concerned.

Bimbowomxn wrote: ↑Sun Oct 04, 2020 7:04 pm Published on the 12th of May.

What has made PCR tests so tremendously useful in this pandemic (odes should probably be sung to their glory), is that they are based on gene technology and identify specific sequences of DNA or, in the case of SARS CoV-2, RNA molecules. Since RNA is extremely specific for a biological entity, this allows extreme specificity and few false positive tests and high positive predictive values - even in contexts with low prevalence.

In a July article in The Spectator, Oxford professor of evidence-based medicine, Carl Heneghan, also refers to the BMJ practice (5). While the pointer used specificity 95% "for illustrative purposes", Heneghan refers to it as "a review" that "reported that the specificity of PCR tests could be as low as 95%". While Heneghan is also only trying to contribute to the understanding of tests, this shows that using a figure like 95% for illustrative purposes may be misunderstood as a reference to the facts, be misleading and give the impression that false positives are very common. Admittedly, Heneghan also writes in The Spectator, that "based on the latest data, the specificity may be as high as 99,9 per cent", but he also states he thinks this is too high.

...we know rising positive cases aren’t due to false positives for a couple of other reasons.

Positive test rates are going up as a percentage of total tests – this is not disputed.

But this can’t be because of an increase in false positives as the rate of false positives remains constant unless the actual method of testing changes, which it hasn’t.

Additionally, if false positives were causing the spike in numbers, it would be uniform across the UK and it isn’t.