This is wonderful, really exciting news. Even if there are mistakes, I'm excited that there is an indication the ifr is much lower than feared.
This means the cfr in SCC could end up being less than 1%? Also, recall SCC has one of the longest life expectancies in the US due to a relatively lower rate of obesity, a lower rate of smoking, access to good healthcare, and a very high median household salary.
I saw the ad on Facebook, and I started filling out the form, but then paused when it said you'd have to wait in line, and it did not mention I'd be waiting in line in my car, so I did not complete the sign-up form. A few thoughts on bias:
1) To its credit, it said it wanted a cross-section of different races and different symptoms. I had never had any symptoms, so it felt like the best opportunity to for me to get a test because most other places seem to require some symptoms. Or maybe people felt like they'd be more likely to qualify if they downplayed their symptoms, because people want a free test conducted by Stanford.
2) I saw the ad around 2-3pm on a Wednesday or a Thursday and it reportedly filled up within hours. Who is Facebooking at that time, and has the schedule flexibility to jump on a test that might be on either Friday or Saturday? Probably not a grocery store clerk or a healthcare worker.
3) One of the testing locations was at Vasona Park in Los Gatos, it is a very nice park in a somewhat wealthy area, adjacent to other wealthy areas like Saratoga. If you look at the SCC dashboard and normalize # of cases / 10,000 people by city, you'll see Saratoga, Los Gatos , Cupertino and Mountain View have much fewer positive cases per 10,000 people. Saratoga and Cupertino (home of Apple) have less than 1/3 the cases per 10,000 people than San Jose (and sadly, Palo ALto has the second highest # of cases per 10,000, possibly due to all the healthcare workers?). Two of the three testing locations were in Mountain View (home of Google) and Los Gatos (home of Netflix). The third location was Hellyer Park in San Jose, but I am less familiar with that area.
If you look at demographic data on the SCC Dashboard, whites have death rates roughly in-line with their share of the population, and Asians are under-represented by almost a third, perhaps because more of them work for tech companies and have been working from home even before the Shelter-in-Place. Hispanics are over-represented by about a third, which I think is reflective of taking a larger share of jobs with a high degree of exposure. My guess is that the study under-represented this demographic -- for example, the ad I saw was written in English and there was no indication they'd accommodate people in other languages.
So yes, my guess is that future studies may come up with a lower multiple. I hope there are many follow-up studies soon. Maybe they can analyze where they may have had biases and try to have a broader, more reflective study the next time.
But let's say they're off by 3x (which is the ratio in cases per 10,000 people in San Jose:Cupertino), that would still be a multiplier of 17-28, which would still be very good news!
Self correction: on second thought, some of the sampling biases mechanisms would work in the opposite direction I initially thought, but I am still very excited by this possibility, even if the multiple changes a bit. In any event, picking parks in Los Gatos and Mountain View could give you a very non-representative sample.
This means the cfr in SCC could end up being less than 1%? Also, recall SCC has one of the longest life expectancies in the US due to a relatively lower rate of obesity, a lower rate of smoking, access to good healthcare, and a very high median household salary.
I saw the ad on Facebook, and I started filling out the form, but then paused when it said you'd have to wait in line, and it did not mention I'd be waiting in line in my car, so I did not complete the sign-up form. A few thoughts on bias:
1) To its credit, it said it wanted a cross-section of different races and different symptoms. I had never had any symptoms, so it felt like the best opportunity to for me to get a test because most other places seem to require some symptoms. Or maybe people felt like they'd be more likely to qualify if they downplayed their symptoms, because people want a free test conducted by Stanford.
2) I saw the ad around 2-3pm on a Wednesday or a Thursday and it reportedly filled up within hours. Who is Facebooking at that time, and has the schedule flexibility to jump on a test that might be on either Friday or Saturday? Probably not a grocery store clerk or a healthcare worker.
3) One of the testing locations was at Vasona Park in Los Gatos, it is a very nice park in a somewhat wealthy area, adjacent to other wealthy areas like Saratoga. If you look at the SCC dashboard and normalize # of cases / 10,000 people by city, you'll see Saratoga, Los Gatos , Cupertino and Mountain View have much fewer positive cases per 10,000 people. Saratoga and Cupertino (home of Apple) have less than 1/3 the cases per 10,000 people than San Jose (and sadly, Palo ALto has the second highest # of cases per 10,000, possibly due to all the healthcare workers?). Two of the three testing locations were in Mountain View (home of Google) and Los Gatos (home of Netflix). The third location was Hellyer Park in San Jose, but I am less familiar with that area.
If you look at demographic data on the SCC Dashboard, whites have death rates roughly in-line with their share of the population, and Asians are under-represented by almost a third, perhaps because more of them work for tech companies and have been working from home even before the Shelter-in-Place. Hispanics are over-represented by about a third, which I think is reflective of taking a larger share of jobs with a high degree of exposure. My guess is that the study under-represented this demographic -- for example, the ad I saw was written in English and there was no indication they'd accommodate people in other languages.
So yes, my guess is that future studies may come up with a lower multiple. I hope there are many follow-up studies soon. Maybe they can analyze where they may have had biases and try to have a broader, more reflective study the next time.
But let's say they're off by 3x (which is the ratio in cases per 10,000 people in San Jose:Cupertino), that would still be a multiplier of 17-28, which would still be very good news!
Self correction: on second thought, some of the sampling biases mechanisms would work in the opposite direction I initially thought, but I am still very excited by this possibility, even if the multiple changes a bit. In any event, picking parks in Los Gatos and Mountain View could give you a very non-representative sample.