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I think the overwhelming majority of people are visiting grocery stores to buy food. (Or have someone in their household doing it) If the studied presume this

by varenc 7y ago

I think the overwhelming majority of people are visiting grocery stores to buy food. (Or have someone in their household doing it) If the studied presume this then it makes more sense.

CydeWeys 7y ago
You can't assume that. I know plenty of people who haven't left their apartments in a month plus, because they're having groceries ordered in. And you completely missed the point that people who are going outside a lot more often are both (a) more likely to have been exposed to COVID-19, and (b) more likely to be encountered by your survey. If there are e.g. 700 daily shoppers and 700 weekly shoppers going to a given store, then if you go on one day and sample every shopper you're not going to get half and half by population as you'd need to for a true random sample; instead, you're going to get 700 daily shoppers and only 100 weekly shoppers! This is a hugely biased sample!
- leereeves 7y ago
  Are you describing the actual study or the study as you're imagining it? Because I imagine the statisticians have thought of these concerns and attempted to correct for them. I find it interesting that this study corresponds to an IFR around 0.5%, similar to the IFR arrived at by other studies using very different methods. Perhaps the statisticians who conduct these studies actually know what they're doing better than Hacker News commenters. And perhaps it's time to accept the politically inconvenient scientific truth these studies are revealing.
  - twomoretime 7y ago
    >similar to the IFR arrived at by other studies using very different methods With the wild range of IFR from so many studies, you could trivially cherry pick supporting studies for a bunch of different numbers, especially if you throw in am error range.
- deleted 7y ago
  [deleted]
- cm2187 7y ago
  The study wasn't one day but one week, and even then, I assume they wouldn't be stupid enough to collect blood from the same person over and over.
  - CydeWeys 7y ago
    There's more than one store in NYC. People shop at a variety of places. Daily shoppers are likely not going to the same store over and over every day. Even during this pandemic I've hit up several different grocery stores and shops, because some things are hard to find.
wtvanhest 7y ago
I’m starting to believe that the difference in opinions on whether these studies are legitimate or not hinges heavily on personal behavior. For my wife and I and kid, we live in SF and order food when we can from grocery. When we can’t, I put on an N99 mask and gloves and buy 2 weeks worth of groceries. Then go through a ritual to be as safe as possible entering the home and bringing groceries in. If someone asks me at the grocery store to take the covid test, no way. How would I even do that safely??? I live in San Francisco though and am worried about the fact that the grocery is 70% instacart workers. Everyone I know in the city (nyc, sf, Boston, Chicago etc.) is trying to use 3rd parties to get their groceries. Everyone I know in the suburbs is going to the store. I believe the reason people read this study differently is that their experience is different. The whole foods in downtown sf would be scary to be in without a mask. And I view it as the riskiest place I have to go. It’s full of gig workers who are taking way more risk than the average person. We will know more when we see the results of the study, but I think we need a more random sample before thinking this NYC study is even remotely close to showing that 20% of NYCers previously had it
- cm2187 7y ago
  I'm afraid the population who has these options (and spends its time on hackernews) is called the 1% for a reason, and probably aren't going to bias the stats significantly.
  - CydeWeys 7y ago
    This doesn't make any sense. Grocery and food delivery is quite affordable. It's not only available to the top 1%. These options are being widely taken advantage of by a large number of people right now way down the economic spectrum. It's not a tiny minority of the wealthiest people patronizing them.
keenmaster 7y ago
At any given point of time, a disproportionate number of shoppers in a store are super-shoppers - people that shop more often than the average person and for longer periods of time. Those people are also more likely to have caught Coronavirus before. Without even getting into online ordering, false positives, etc...this phenomenon alone may confound the test results.

by varenc 7y ago

I think the overwhelming majority of people are visiting grocery stores to buy food. (Or have someone in their household doing it) If the studied presume this then it makes more sense.

CydeWeys 7y ago

You can't assume that. I know plenty of people who haven't left their apartments in a month plus, because they're having groceries ordered in. And you completely missed the point that people who are going outside a lot more often are both (a) more likely to have been exposed to COVID-19, and (b) more likely to be encountered by your survey. If there are e.g. 700 daily shoppers and 700 weekly shoppers going to a given store, then if you go on one day and sample every shopper you're not going to get half and half by population as you'd need to for a true random sample; instead, you're going to get 700 daily shoppers and only 100 weekly shoppers! This is a hugely biased sample!

leereeves 7y ago
Are you describing the actual study or the study as you're imagining it? Because I imagine the statisticians have thought of these concerns and attempted to correct for them. I find it interesting that this study corresponds to an IFR around 0.5%, similar to the IFR arrived at by other studies using very different methods. Perhaps the statisticians who conduct these studies actually know what they're doing better than Hacker News commenters. And perhaps it's time to accept the politically inconvenient scientific truth these studies are revealing.
- twomoretime 7y ago
  >similar to the IFR arrived at by other studies using very different methods With the wild range of IFR from so many studies, you could trivially cherry pick supporting studies for a bunch of different numbers, especially if you throw in am error range.
deleted 7y ago
[deleted]
cm2187 7y ago
The study wasn't one day but one week, and even then, I assume they wouldn't be stupid enough to collect blood from the same person over and over.
- CydeWeys 7y ago
  There's more than one store in NYC. People shop at a variety of places. Daily shoppers are likely not going to the same store over and over every day. Even during this pandemic I've hit up several different grocery stores and shops, because some things are hard to find.

wtvanhest 7y ago

I’m starting to believe that the difference in opinions on whether these studies are legitimate or not hinges heavily on personal behavior. For my wife and I and kid, we live in SF and order food when we can from grocery. When we can’t, I put on an N99 mask and gloves and buy 2 weeks worth of groceries. Then go through a ritual to be as safe as possible entering the home and bringing groceries in. If someone asks me at the grocery store to take the covid test, no way. How would I even do that safely??? I live in San Francisco though and am worried about the fact that the grocery is 70% instacart workers. Everyone I know in the city (nyc, sf, Boston, Chicago etc.) is trying to use 3rd parties to get their groceries. Everyone I know in the suburbs is going to the store. I believe the reason people read this study differently is that their experience is different. The whole foods in downtown sf would be scary to be in without a mask. And I view it as the riskiest place I have to go. It’s full of gig workers who are taking way more risk than the average person. We will know more when we see the results of the study, but I think we need a more random sample before thinking this NYC study is even remotely close to showing that 20% of NYCers previously had it

cm2187 7y ago
I'm afraid the population who has these options (and spends its time on hackernews) is called the 1% for a reason, and probably aren't going to bias the stats significantly.
- CydeWeys 7y ago
  This doesn't make any sense. Grocery and food delivery is quite affordable. It's not only available to the top 1%. These options are being widely taken advantage of by a large number of people right now way down the economic spectrum. It's not a tiny minority of the wealthiest people patronizing them.

keenmaster 7y ago

At any given point of time, a disproportionate number of shoppers in a store are super-shoppers - people that shop more often than the average person and for longer periods of time. Those people are also more likely to have caught Coronavirus before. Without even getting into online ordering, false positives, etc...this phenomenon alone may confound the test results.