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Preliminary test results suggest 21% of NYC residents have Covid antibodies

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Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#611

Post by timr »

zamfi wrote: post #593
timr wrote: post #578

Earlier quoted context omitted.

"Yes, which is clearly true, no?" No. As far as I can tell, approximately 100% of people in New York want to be tested, for many different reasons. You're assuming something and projecting it as truth. "These studies would ideally be true random samples so that we can know what the true infection rate is." But by your own logic, there can be no "random sample"...we can't tie people down and force them to be tested, s…

> No. As far as I can tell, approximately 100% of people in New York want to be tested, for many different reasons. You're assuming something and projecting it as truth. In NY, the issue was not about wanting to be tested, it was about "are you there when they're picking people to test"; quoting from the article, which is very thin on info, people were selected "at 40 locations that included grocery and big-box store…

"In NY, the issue was not about wanting to be tested, it was about "are you there when they're picking people to test""

It's the same critique. If you pick the people anywhere other than from their home, the argument is that they're not at home, therefore they're more likely to have it.

OK, so how do you get them in their homes? If you solicit them on the internet, then there's sample bias because you're telling them they'll be tested. If you knocking door-to-door, it's the same thing: you have to tell them what you're going to do, so you're "selecting for people who want to be tested". You can't win.

"Or at least pick people truly at random,"

You can't force people to take blood tests against their will. You have to tell them what you're doing, and why you're doing it, and they must consent to participate. The same objection always applies to any "random" selection of humans: it's biased towards the people in the place at the time of selection, who agreed to be selected.

"you can at least try to account for the ways in which your sample is likely to be different from a truly random sample."

Right, as all legitimate researchers in this area do.

As I said before: this is all just a highbrow way of rejecting studies for lowbrow reasons. You will never find a survey without some form of sample bias. You control for it and move on.

We are now seeing multiple independent serological surveys with different methods pointing in the same direction. It isn't a methodological error.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#612

Post by Mikeb85 »

newacct583 wrote: post #529
CubsFan1060 wrote: post #373

Earlier quoted context omitted.

Which is about 1/2 of what die in a normal year. The real question is how much do those circles overlap. Are we saving lives, or are people now dying in June that would have died in November anyway?

This is like the third or fourth spot I've seen on this very site where people are postulating that covid deaths would have really died in "months" anyway. Why is this so weirdly consistent? To be clear: there is absolutely no evidence for a number like that, none at all. Typical at-risk patients with comorbidity like advanced age or obesity are routinely expected to live for decades. Actual conditions with a death-i…

The vast majority of deaths in Canada (for example since I live here) are those who are 80+ and around half lived in nursing homes. Given average life expectancy in our country is only 82, the vast majority of coronavirus victims' probability of death any given year was quite high.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#613

Post by smacktoward »

Mikeb85 wrote: post #610
aazaa wrote: post #317

> In his press conference today, Governor Cuomo revealed the preliminary results of a first-phase antibody test that surveyed 3,000 New Yorkers over two days in 19 counties at 40 locations that included grocery and big-box stores. The sample suggests that 13.9% of New York State residents have the antibodies, meaning they had the virus at one point and recovered. Of the regions tested–Long Island, NYC, Westchester/Ro…

I literally made the same comment a few days ago but here goes: every thread about a study such as this one is has criticisms concerning the scientific accuracy even though all these studies point to the same conclusion and not one of them provide evidence to the contrary. This isn't exact science, we're in the middle of a pandemic. But all these antibody studies are pointing towards the same conclusion.

Do they all use the same testing mechanism? If they do, a flaw in that mechanism could result in them all being incorrect or misleading in the same way(s).

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#614

Post by DeonPenny »

Mikeb85 wrote: post #610
aazaa wrote: post #317

> In his press conference today, Governor Cuomo revealed the preliminary results of a first-phase antibody test that surveyed 3,000 New Yorkers over two days in 19 counties at 40 locations that included grocery and big-box stores. The sample suggests that 13.9% of New York State residents have the antibodies, meaning they had the virus at one point and recovered. Of the regions tested–Long Island, NYC, Westchester/Ro…

I literally made the same comment a few days ago but here goes: every thread about a study such as this one is has criticisms concerning the scientific accuracy even though all these studies point to the same conclusion and not one of them provide evidence to the contrary. This isn't exact science, we're in the middle of a pandemic. But all these antibody studies are pointing towards the same conclusion.

I can't believe people are still screaming false results at this point every single random sampling has been the same or point to more infections. At this point based on everyone's method of random sampling that should merit the badge of random sampling, but people argue it on every post.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#615

Post by tigershark »

aazaa wrote: post #317

> In his press conference today, Governor Cuomo revealed the preliminary results of a first-phase antibody test that surveyed 3,000 New Yorkers over two days in 19 counties at 40 locations that included grocery and big-box stores. The sample suggests that 13.9% of New York State residents have the antibodies, meaning they had the virus at one point and recovered. Of the regions tested–Long Island, NYC, Westchester/Ro…

The biggest problem looking at these tests is that they are completely on the opposite side compared to the mortality estimated using South Korea numbers. We know for a fact that South Koreans tracked pretty much every single person with covid given that their new cases are increasing by a single digit per day. We know that as of today they have 10708 cases and 240 deaths, with still 1967 active cases. This give us a lower bound for the mortality at 2.2%. I think this is the best way to estimate mortality and I think that a lot of studies are giving numbers for the infected that are just out of touch with reality. I remember an Oxford study that was saying that half the UK was infected at the beginning of April. Those numbers were simply insane. I still don’t have a perfect explanation why the mortality numbers from the antibody tests seem so low, but I think that the accuracy of these tests or the way they select the people to be tested may be involved. Do you see any flaw in using South Korea numbers to calculate the mortality?

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#616

Post by JackFr »

koheripbal wrote: post #546
mannykannot wrote: post #499

Earlier quoted context omitted.

NYC is not suburbia. I believe a higher percentage are still working outside of their homes (and, in many cases, that also means travelling on public transport), and a smaller percentage have the financial and transport resources to significantly reduce the frequency of their shopping trips. Apartment living means a greater exposure to your neighbors whenever you do enter or exit. The sampling in NYC, while far from…

As a (40-something) NYC resident, I don't believe that is accurate. Half of the people I know are working from home and stocked up on 1-2 months of food at the outset of this. The other half left the city and are now staying with friends/family in other states or have rented homes elsewhere. Those that did stay and still need food (ie produce) are having it delivered. People who are shopping in stores are absolutely…

> Half of the people I know are working from home and stocked up on 1-2 months of food at the outset of this.

Seriously? Your personal network is evidence the this study is useless because of sampling bias?

Everyone I know voted for Hilary Clinton and yet here we are.

> People who are shopping in stores are absolutely a very biased sample.

People who have jobs that allow them to work from home are a very biased sample. How many grocery stockers are there in NYC compared to let’s say, software developers? I suspect you haven’t a clue, since by your own admission you don’t know a single person who needs to leave their home to work. So maybe your mental model if who makes up the population is skewed.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#617

Post by JackFr »

wtvanhest wrote: post #568
koheripbal wrote: post #546

Earlier quoted context omitted.

As a (40-something) NYC resident, I don't believe that is accurate. Half of the people I know are working from home and stocked up on 1-2 months of food at the outset of this. The other half left the city and are now staying with friends/family in other states or have rented homes elsewhere. Those that did stay and still need food (ie produce) are having it delivered. People who are shopping in stores are absolutely…

I’m a resident of SF downtown and previously DC and Boston. Everyone I know has stopped leaving their apartments/condos except for fresh air and are trying not to go to any stores. When possible are having food delivered. My friends in NYC have all left except for one who has a large apartment and no family without taking a flight. I think people see these studies of places they visited once and determine that those…

Please stop using “everyone I know” as a data point, especially when criticizing someone else’s sampling bias.

I am suffocating under the irony.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#618

Post by FiberBundle »

tigershark wrote: post #615
aazaa wrote: post #317

> In his press conference today, Governor Cuomo revealed the preliminary results of a first-phase antibody test that surveyed 3,000 New Yorkers over two days in 19 counties at 40 locations that included grocery and big-box stores. The sample suggests that 13.9% of New York State residents have the antibodies, meaning they had the virus at one point and recovered. Of the regions tested–Long Island, NYC, Westchester/Ro…

The biggest problem looking at these tests is that they are completely on the opposite side compared to the mortality estimated using South Korea numbers. We know for a fact that South Koreans tracked pretty much every single person with covid given that their new cases are increasing by a single digit per day. We know that as of today they have 10708 cases and 240 deaths, with still 1967 active cases. This give us a…

South Korea apparently has conducted 11500 tests/ 1m population. It's ridiculous to claim that they detected every covid case and to suggest that their cfr is a lower bound for the ifr.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#619

Post by zamfi »

timr wrote: post #611
zamfi wrote: post #593

Earlier quoted context omitted.

> No. As far as I can tell, approximately 100% of people in New York want to be tested, for many different reasons. You're assuming something and projecting it as truth. In NY, the issue was not about wanting to be tested, it was about "are you there when they're picking people to test"; quoting from the article, which is very thin on info, people were selected "at 40 locations that included grocery and big-box store…

"In NY, the issue was not about wanting to be tested, it was about "are you there when they're picking people to test"" It's the same critique. If you pick the people anywhere other than from their home, the argument is that they're not at home, therefore they're more likely to have it. OK, so how do you get them in their homes? If you solicit them on the internet, then there's sample bias because you're telling them…

> > you can at least try to account for the ways in which your sample is likely to be different from a truly random sample. > Right, as all legitimate researchers in this area do.

Yeah, obviously we agree here. So: how do you effectively control for them in this case? That's my point. It's hard, and you haven't offered any mechanism for this particular case, just assurances that people who know what they're doing do in fact know what they're doing.

Are you one of those people? Please fill us in on what they're doing to address sample bias. They "try to control for it" -- how in this case? So far you've offered nothing specific, just that experts control for it, and you're implying that it's illegitimate to question whether there might be a systemic bias because all the cited studies seem to select populations more likely to be infected.

> OK, so how do you get them in their homes? If you solicit them on the internet, then there's sample bias because you're telling them they'll be tested. If you knocking door-to-door, it's the same thing: you have to tell them what you're going to do, so you're "selecting for people who want to be tested". You can't win.

Am I understanding correctly that you're saying that because you can't get a perfectly random sample you shouldn't try to minimize selection bias? You can't "win", but you can get closer than these studies did. There's a clear difference between a Facebook ad "Stanford seeks people for COVID-19 tests" and "Your number was chosen at random and we'd like to test you for COVID-19 in the interest of science."

One should absolutely try to minimize selection bias, in addition to controlling for its inevitability. In Germany, as you propose, they are selecting people at random from a central database of residents, which is not correlated with whether they have symptoms, feel comfortable shopping in public, etc. That is better than showing up at a grocery store, clearly, right?

As for people who agree to be selected, yes, there's nothing we can do about that in liberal societies. I'd like to know what this rate is. In Germany, I recall that it was low.

> this is all just a highbrow way of rejecting studies for lowbrow reasons

OK, this is the second time you've implied that I'm uninformed, or am acting in bad faith or with bad motives (or whatever "lowbrow reasons" means). None of these are true. I've ignored the personal nature of your vague dismissals up to now in the interest of conversation, but I'm done doing so.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#620

Post by tigershark »

FiberBundle wrote: post #618
tigershark wrote: post #615

Earlier quoted context omitted.

The biggest problem looking at these tests is that they are completely on the opposite side compared to the mortality estimated using South Korea numbers. We know for a fact that South Koreans tracked pretty much every single person with covid given that their new cases are increasing by a single digit per day. We know that as of today they have 10708 cases and 240 deaths, with still 1967 active cases. This give us a…

South Korea apparently has conducted 11500 tests/ 1m population. It's ridiculous to claim that they detected every covid case and to suggest that their cfr is a lower bound for the ifr.

They tested everyone that was in contact with a reported case, I never claimed that they tested the whole population. How do you explain that they are showing only a single digit increase of new cases per day if, as you assert, there is a huge number of unaccounted cases?
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