8 ms·

So, I just copied the data from WHO sitreps and the total-cases diff of diffs has been increasingly negative for three of the last four days. So it's still gett

So, I just copied the data from WHO sitreps and the total-cases diff of diffs has been increasingly negative for three of the last four days. So it's still getting worse, but the second derivative might be negative. And those are WHO numbers, so he surely knew that when he put the tweet out (it's enough that you can just see it in the scatterplot). So I wonder if he's saying that to stay out ahead. What he would really want now is for people to not let up. Keep people on alert, and clamp down on the respiratory human-to-human transmission. Keep that second derivative negative!

vosper 7y ago
> So, I just copied the data from WHO sitreps and the total-cases diff of diffs has been increasingly negative for three of the last four days. So it's still getting worse, but the second derivative might be negative. Could you explain what this means in layman's terms?
- adrianN 7y ago
  The rate at which new people get infected is going down.
  - PeterisP 7y ago
    Only if we assume that the published rates of new infection reflect reality. The statistics refer to diagnosis of 2019-nCov based on conclusive test results. They do not include diagnosis solely made on symptoms - if somebody in China had flu-like symptoms and died from pneumonia, that's not considered a diagnosis of 2019-nCov infection and thus it's not an 2019-nCov death unless proper tests were performed. Even if we assume that all the test results are reported, we know that large quantities of suspected cases in Wuhan are not tested - hospitals report there's an insufficient quantity of RNA test kits available, there are some reports that outpatients aren't tested, and bed capacity is limited, so anybody who does not have space in the hospital system is not tested. And if they die, they're excluded from statistics of 2019-nCov patients because they were not tested. So if you have a system that's capable to test X people per day, even if you report all the test results perfectly honestly, you're not going to see more than X new infections per day... no matter how many new infections you actually have. If it's nontrivial for Japan to test 3600 people quarantined on a ship, how would it be possible to test everyone who's sneezing from 11 million people quarantined in a city?
- yarg 7y ago
  The second derivative is the acceleration. If it's negative it can still be getting worse (positive first derivative), but it's slowing down. The second derivative is the rate at which the rate of change is changing.
  - blackrock 7y ago
    Sounds about right. This will get worse before it gets better. This is an interesting chart to new map the new daily infection rate. https://twitter.com/Tom_Fowdy/status/1226659915160117248 https://twitter.com/Tom_Fowdy/status/1226659915160117248 The daily count of new cases is going down. China’s containment effort might be successful. However, this may not account for everything. * They have limited daily testing kits. Especially in the early days of this crisis. * There may be people who had died, but they didn’t get tested, so they won’t be counted in this statistic. The moral dilemma is: Do you burn a precious test kit on a dead corpse to verify that they had the virus, or do you save it for someone still living? * The city and the province’s medical system is under severe strain, and there are not enough supplies to go around. They may not even be able to account for everything or everyone, because their medical system is suffering from a massive denial of service attack right now. * They may have ramped up test kit production this weekend to 10k/day, so this may skew the numbers higher, as they are able to test more people. * There are reports that the testing is not fully accurate, if you’re in the early stage, where the virus hasn’t generated enough markers to be detected yet. So, this is a false negative, where you are actually infected, but the test says that you are not. This might be why they will only clear you, if you get two negative tests in a row.
    - ImaCake 7y ago
      Yes, but likely at a predictable and slowing rate. Some graphs I've seen look something like a bell curve.
    - DyslexicAtheist 7y ago
      if a virus would wipe out say 50% or 75% of humanity, it would be terrible for us but wouldn't be that bad for mother nature. It may provide a couple of decades (if not centuries) in which nature is able to recover from us. I think thanks to global warming, there will be many more diseases coming our way. Things that our immune system has never previously had to fight against and for which there is no cure.
dhx 7y ago
WHO daily situation report data (global) charted and updated each day: https://w.wiki/Gk4 https://w.wiki/Gk4
mantap 7y ago
The numbers from Wuhan are simply wrong and we have no idea how many people there are infected or how many have died. So you should discard all data from Wuhan at least before doing your analysis. The whole city is under quarantine, people may not be able to get to a hospital. Even if they do, hospitals are overloaded and beyond capacity. If people there die before being tested their death won't be counted as being from coronavirus. If they have mild symptoms but are not in a serious condition they would be stupid to go to a hospital and get tested (and risk getting infected). And China is a communist country so the numbers should be taken with a large grain of salt anyway.
- viraptor 7y ago
  People have really strong reaction here. Outside of popular news, we know how to deal with incomplete data and biased numbers. This probably should be told more often when reporting the cases on the TV, but I expect anyone actually having impact on the issue understands that any actual counts we get are a lower bound, that testing resources and travel regulation affects the reports, and how to take into account other reporting biases. This is not a new idea.
  - mantap 7y ago
    I was replying to this: "I just copied the data from WHO sitreps and the total-cases diff of diffs has been increasingly negative for three of the last four days." In any case I disagree that the data from Wuhan contains any information. Even if you can magically model away all the problems in the data, the Chinese government is still a disreputable source. Chinese state media is notorious for only showing the CCP in a good light. When you see the words 'Xinhua News', what comes to mind? Propaganda right? I don't understand why people think that China is publishing the truth now, when China is in crisis and freedom of speech is trending on Weibo. Surely this is the time to turn propaganda up to 11. These numbers are the most powerful tool that the Chinese government has for propaganda right now. And given their penchant for it, the baseline assumption should be that they are being massaged into the narrative that Beijing wants to tell.
  - PeterisP 7y ago
baq 7y ago
the problem with official data is that it fits a quadratic curve so well it's hard to believe it's true. https://www.reddit.com/r/dataisbeautiful/comments/ez13dv/oc_quadratic_coronavirus_epidemic_growth_model/fgkkh59/ https://www.reddit.com/r/dataisbeautiful/comments/ez13dv/oc_...
- reagent_finder 7y ago
  "Hey Xi, what's going on, this latest batch of infected is enormous! Is there something going on? We need to get on this now!" "Oh whoops, we accidentally sent you next week's numbers." Oh my WTF, they plonked the numbers into a quadratic and have so far predicted 5 days of deaths accurately.
- hef19898 7y ago
  Couldn't it just be that the virus, and the epidemic, simply behave like the are supposed to?
  - baq 7y ago
    i'm not sure if we know how the novel coronavirus 2019 is supposed to behave.
    - hef19898 7y ago
      because there are already Coronaviruses out in the wild. AFAIK causing quite a lot of colds every year. Then we know a lot about SARS and MERS. And the new Corona virus is having the shit anlyzed out of it. Plus We know a lot about epidemics in general. So no, we don't have to reinvent the last couple of centuries regarding epidimiology research, everytime a new disease springs its head somewhere, and every "data scientist" on the internet tries to fit it in some kind of model without the necessary domain knowledge.
mikechen233 7y ago
I think each day the infected count increases 2000 to 3000. It indicates a capacity limits at the health care system to diagnose and confirm an infected case.
- asah 7y ago
  "3.6 Roentgen not great but also not terrible"
- xbmcuser 7y ago
  To me the new infection numbers hovering around 3000 means they don't have capacity to test more or faster. Thats the biggest problem in Wuhan that the healthcare systems got overwhelmed so they are still trying to catch up. Where as rest of the cities got enough of a warning to maybe curtail the spread. With people themselves isolating themselves so that they don't catch the virus I personally feel the virus won't spread as fast in other places.

vosper 7y ago

> So, I just copied the data from WHO sitreps and the total-cases diff of diffs has been increasingly negative for three of the last four days. So it's still getting worse, but the second derivative might be negative. Could you explain what this means in layman's terms?

adrianN 7y ago
The rate at which new people get infected is going down.
- PeterisP 7y ago
  Only if we assume that the published rates of new infection reflect reality. The statistics refer to diagnosis of 2019-nCov based on conclusive test results. They do not include diagnosis solely made on symptoms - if somebody in China had flu-like symptoms and died from pneumonia, that's not considered a diagnosis of 2019-nCov infection and thus it's not an 2019-nCov death unless proper tests were performed. Even if we assume that all the test results are reported, we know that large quantities of suspected cases in Wuhan are not tested - hospitals report there's an insufficient quantity of RNA test kits available, there are some reports that outpatients aren't tested, and bed capacity is limited, so anybody who does not have space in the hospital system is not tested. And if they die, they're excluded from statistics of 2019-nCov patients because they were not tested. So if you have a system that's capable to test X people per day, even if you report all the test results perfectly honestly, you're not going to see more than X new infections per day... no matter how many new infections you actually have. If it's nontrivial for Japan to test 3600 people quarantined on a ship, how would it be possible to test everyone who's sneezing from 11 million people quarantined in a city?
yarg 7y ago
The second derivative is the acceleration. If it's negative it can still be getting worse (positive first derivative), but it's slowing down. The second derivative is the rate at which the rate of change is changing.
- blackrock 7y ago
  Sounds about right. This will get worse before it gets better. This is an interesting chart to new map the new daily infection rate. https://twitter.com/Tom_Fowdy/status/1226659915160117248 https://twitter.com/Tom_Fowdy/status/1226659915160117248 The daily count of new cases is going down. China’s containment effort might be successful. However, this may not account for everything. * They have limited daily testing kits. Especially in the early days of this crisis. * There may be people who had died, but they didn’t get tested, so they won’t be counted in this statistic. The moral dilemma is: Do you burn a precious test kit on a dead corpse to verify that they had the virus, or do you save it for someone still living? * The city and the province’s medical system is under severe strain, and there are not enough supplies to go around. They may not even be able to account for everything or everyone, because their medical system is suffering from a massive denial of service attack right now. * They may have ramped up test kit production this weekend to 10k/day, so this may skew the numbers higher, as they are able to test more people. * There are reports that the testing is not fully accurate, if you’re in the early stage, where the virus hasn’t generated enough markers to be detected yet. So, this is a false negative, where you are actually infected, but the test says that you are not. This might be why they will only clear you, if you get two negative tests in a row.
  - ImaCake 7y ago
    Yes, but likely at a predictable and slowing rate. Some graphs I've seen look something like a bell curve.
  - DyslexicAtheist 7y ago
    if a virus would wipe out say 50% or 75% of humanity, it would be terrible for us but wouldn't be that bad for mother nature. It may provide a couple of decades (if not centuries) in which nature is able to recover from us. I think thanks to global warming, there will be many more diseases coming our way. Things that our immune system has never previously had to fight against and for which there is no cure.

dhx 7y ago

WHO daily situation report data (global) charted and updated each day: https://w.wiki/Gk4 https://w.wiki/Gk4

mantap 7y ago

The numbers from Wuhan are simply wrong and we have no idea how many people there are infected or how many have died. So you should discard all data from Wuhan at least before doing your analysis. The whole city is under quarantine, people may not be able to get to a hospital. Even if they do, hospitals are overloaded and beyond capacity. If people there die before being tested their death won't be counted as being from coronavirus. If they have mild symptoms but are not in a serious condition they would be stupid to go to a hospital and get tested (and risk getting infected). And China is a communist country so the numbers should be taken with a large grain of salt anyway.

viraptor 7y ago
People have really strong reaction here. Outside of popular news, we know how to deal with incomplete data and biased numbers. This probably should be told more often when reporting the cases on the TV, but I expect anyone actually having impact on the issue understands that any actual counts we get are a lower bound, that testing resources and travel regulation affects the reports, and how to take into account other reporting biases. This is not a new idea.
- mantap 7y ago
  I was replying to this: "I just copied the data from WHO sitreps and the total-cases diff of diffs has been increasingly negative for three of the last four days." In any case I disagree that the data from Wuhan contains any information. Even if you can magically model away all the problems in the data, the Chinese government is still a disreputable source. Chinese state media is notorious for only showing the CCP in a good light. When you see the words 'Xinhua News', what comes to mind? Propaganda right? I don't understand why people think that China is publishing the truth now, when China is in crisis and freedom of speech is trending on Weibo. Surely this is the time to turn propaganda up to 11. These numbers are the most powerful tool that the Chinese government has for propaganda right now. And given their penchant for it, the baseline assumption should be that they are being massaged into the narrative that Beijing wants to tell.
- PeterisP 7y ago

baq 7y ago

the problem with official data is that it fits a quadratic curve so well it's hard to believe it's true. https://www.reddit.com/r/dataisbeautiful/comments/ez13dv/oc_quadratic_coronavirus_epidemic_growth_model/fgkkh59/ https://www.reddit.com/r/dataisbeautiful/comments/ez13dv/oc_...

reagent_finder 7y ago
"Hey Xi, what's going on, this latest batch of infected is enormous! Is there something going on? We need to get on this now!" "Oh whoops, we accidentally sent you next week's numbers." Oh my WTF, they plonked the numbers into a quadratic and have so far predicted 5 days of deaths accurately.
hef19898 7y ago
Couldn't it just be that the virus, and the epidemic, simply behave like the are supposed to?
- baq 7y ago
  i'm not sure if we know how the novel coronavirus 2019 is supposed to behave.
  - hef19898 7y ago
    because there are already Coronaviruses out in the wild. AFAIK causing quite a lot of colds every year. Then we know a lot about SARS and MERS. And the new Corona virus is having the shit anlyzed out of it. Plus We know a lot about epidemics in general. So no, we don't have to reinvent the last couple of centuries regarding epidimiology research, everytime a new disease springs its head somewhere, and every "data scientist" on the internet tries to fit it in some kind of model without the necessary domain knowledge.

mikechen233 7y ago

I think each day the infected count increases 2000 to 3000. It indicates a capacity limits at the health care system to diagnose and confirm an infected case.

asah 7y ago
"3.6 Roentgen not great but also not terrible"
xbmcuser 7y ago
To me the new infection numbers hovering around 3000 means they don't have capacity to test more or faster. Thats the biggest problem in Wuhan that the healthcare systems got overwhelmed so they are still trying to catch up. Where as rest of the cities got enough of a warning to maybe curtail the spread. With people themselves isolating themselves so that they don't catch the virus I personally feel the virus won't spread as fast in other places.