Understanding coronavirus statistics

The data quality showing the spread of the coronavirus is poor. The data from the Hubei province (the origin of the virus) is still wildly different from the data from elsewhere and so we need to analyse the data in separate parts. While the numbers don’t look as bad when analysed this way, I note the economic impact is driven by the number of shutdowns and quarantines, not by the number of cases. 

I generally separate the data into three parts: (a) Hubei (b) the rest of Mainland China (c) the rest of the World for analysis.

Investment Impacts

See this recent post for more detail on the investment impacts. My core thesis is the economic impact of the virus is not particularly related to the number of deaths but more related to the measures.

In some respects, they are inversely correlated. An unusually strict shutdown/quarantine would likely have a more significant economic impact but lead to fewer deaths and a slower spread of the virus. In other respects, they are correlated. More cases/deaths will lead to stricter quarantine conditions.

I note already the travel bans and quarantine measures exceed anything implemented with SARS in 2003.   

Total Deaths 

It is pretty clear from this chart the deaths in Hubei are on a different scale to the rest of China:

Deaths from coronavirus

Total Cases

So, it seems suspicious that the number of cases in Hubei was roughly the same as the rest of China ten days ago, and still only a little more than double. 

Some of this may be a lack of test facilities, some of it may be a bureaucratic cover-up. Some might be that hospitals are over-run in Hubei and so can’t give the same care as elsewhere. Or, maybe there is a different factor creating this issue.

Total Chinese coronavirus Cases

New coronavirus cases

The numbers for the rest of the World are still tiny. And, in reality, aren’t a measure of cases elsewhere as much as they are of travellers bringing the virus with them. 

Rest of the world total coronavirus cases

Mortality Rate

The mortality rate is where we can see distinct differences in data. Dividing the number of deaths by the number of cases during the early stages of an outbreak is very misleading. People who were diagnosed today with the disease are still alive, but they still might die from the disease in the coming days.

A better way is to compare the current deaths to the number of cases from “x” days ago. We still don’t know how many days we should be looking back. The stats so far suggest that the median days from the first symptom to death is 14. But with a broad range from 6 to 41. And, we don’t know how long on average after the first symptom a person would take to become a case.

The below charts show the death rate if the right period to look back is five days, ten days or 15 days. Using data without Hubei, a mortality rate of somewhere between 1% and 4% is likely. The Rest of World data is similar but with only 2 deaths not worth looking at yet.

  Rest of China mortality rate with different lag periods

Using Hubei data suggests the mortality rate is somewhere between 18% and 90%. This seems improbable – to put it mildly. If we trust the older Hubei data, there are now more people dead than what there were cases 2 weeks ago. 

Hubei / Wuhan mortality rate with different lag periods


Keep in mind that almost all “rest of the world” cases so far are really Chinese cases that have travelled. It will be weeks before we know if there will be outbreaks outside of China that will need quarantine measures.

The number of cases within China is probably over 200,000 already – significantly higher than reported.

Given this, economic outcomes are likely to be:

  • extensive shutdowns and travel bans in China for at least three months, most likely longer
  • a relatively good chance of shutdowns and travel bans in other countries, especially close neighbours

When looking at any coronavirus data, I recommend separating the data before analysing.


Damien Klassen is Head of Investments at the Macrobusiness Fund, which is powered by Nucleus Wealth.

The information on this blog contains general information and does not take into account your personal objectives, financial situation or needs. Past performance is not an indication of future performance. Damien Klassen is an authorised representative of Nucleus Wealth Management, a Corporate Authorised Representative of Nucleus Advice Pty Ltd – AFSL 515796.

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  1. reusachtigeMEMBER

    Past some paranoid people with those god awful masks on yesterday. Don’t they realise how stupid they look?

    • Quite! And in your case the public would be unable to admire your impressive facial furniture!

      • ErmingtonPlumbingMEMBER

        Yes and the straps would clash with those splendid pendulum ear rings Reuda would never be seen without.

        He’s an odd Fellow really.

        • Stewie GriffinMEMBER

          Got to love ZH they are the masters of Conspiracy theory:

          According to the report, late on Saturday evening, Tencent, on its webpage titled “Epidemic Situation Tracker”, showed confirmed cases of novel coronavirus (2019nCoV) in China as standing at 154,023, 10 times the official figure at the time. It listed the number of suspected cases as 79,808, four times the official figure.

          And while the number of cured cases was only 269, well below the official number that day of 300, most ominously, the death toll listed was 24,589, vastly higher than the 300 officially listed that day.

          Moments later, Tencent updated the numbers to reflect the government’s “official” numbers that day.

          This was not the first time Tencent has done this: as Taiwan Times notes, Chinese netizens have noticed that Tencent has on at least three occasions posted extremely high numbers, only to quickly lower them to government-approved statistics.

          This is where it gets even more bizarre: contrary to claiming that this was just a “fat finger” mistyping of data, observant Chinese netizens also noticed that each time the screen with the large numbers appears, it shows a comparison with the previous day’s data which demonstrates a “reasonable” incremental increase, much like comparisons of official numbers.

          This led many in the mainland to speculate that Tencent has two sets of data, the real data and “processed” data.


          Interestingly or perhaps disconcertingly, about two weeks ago Zero Hedge posted an article from Jonathan Read, a UK expert on the transmission and evolutionary dynamics of infectious diseases, who has published a paper that predicted in ten days the number of infected people in Wuhan to be greater than 250 thousand (with an prediction interval, 164,602 to 351,396).


          Of course it would be conspiracy theory to suggest that China is running two sets of statistical data – real and approved. They certainly haven’t been guilty of doing so in the past, and it is mere tin foil coincidence that the numbers accidentally released in error by Tencent was broadly in the range of some UK gwelio. Also is just rumour and scuttlebutt that China has been running their crematoriums 24/7.

          I guess as the virus becomes established in more transparent locations and population centres, the truth will emerge one way or the other…. shouldn’t have to wait too long.

  2. Good thinking… coming for all of us, eventually.

    The UK has told 30k Brits to leave China immediately, by any means, and self isolate themselves once home for two weeks!!! Too bad for people sharing in the taxi, train, bus, plane, airport terminal, and family… what a complete mess, whole thing run by numpty’s.

    • As I posited recently, you wouldn’t want to undertake any air travel right now as you have no idea who’ll be sat next to (or near). Make it a long haul flight and it’s going to be a seriously uncomfortable flight, esp if one of your neighbors is sneezing and coughing.

      • Yeah I definitely thought so too. Even domestic flights are a no go because people will just do what they want and if it gets inconvinient to stay home, they won’t!
        This will be a huge sticking point for growth. The more they let people in, the more people will speculate that they will catch it and stay home.
        Sad irony then at the moment immigration now will result in lower consumption and all that goes with it.
        Hope they find a cure soon.

  3. PalimpsestMEMBER

    I haven’t noticed any cases reported from Africa. I guess no one from Hubei travels there.

  4. Seems to me that the number of deaths to number recovered has useful information during thrse early stages. It will be imperfect data too, confounded by those not sick enough to ever go to hospital. Still, it could be worth watching.

  5. Jevons ghostMEMBER

    Waiting for some credible (!) mortality data. Age, sex and co-morbidities. Figuratively speaking right now we’re at 30 minutes after the polls have closed.


    This is more made up than anything I have seen anywhere and taken directly from the comment section in another post – absurd.

    Again – things like this

    “A better way is to compare the current deaths to the number of cases from “x” days ago. ”

    Really – does that take into account the new information on how to deal with the problem we did not have ten days ago ? Does that take into consideration that people dying previously had no idea they even had the illness ? How long for ? Its a ridiculous attempt at nothing short of inflating the numbers to secure a more panicked response.

    “The number of cases within China is probably over 200,000 already – significantly higher than reported.”

    Just make sh1t up next time mate. Don’t worry about the military on every travel point in China checking people, travel restrictions across the entire country – “its not 20,000 as reported – yup – definitely 200,000” – you should honestly go get a job at CoreLogic – makey-upy-stuffy is their bread and butter – you’d fit right in.