The French are fleeing Paris in massive numbers before the next lockdown.

Discussion in 'Politics' started by Amun Ra, Oct 31, 2020.

  1. gwb-trading

    gwb-trading

    I provided the math for the U.S. based the information found on the Worldmeters site today for deaths and cases in the U.S.
    https://www.worldometers.info/coronavirus/

    If you want the current CFR figure for the world then 1,203,164 deaths / 46,628,126 cases is 2.58% --- which pretty much matches the current U.S. calculation of CFR.
     
    #21     Nov 1, 2020
  2. Cuddles

    Cuddles

    CFR is best estimated using closed cases
     
    #22     Nov 1, 2020
  3. gwb-trading

    gwb-trading

    Of course.... and as noted by an entire section in Worldmeter on CFR calcualtions.... until a pandemic is over then the precise CFR with closed cases will not be known. There are methods of providing the most accurate CFR while a pandemic is ongoing -- including the reality that deaths are offset in time T several weeks from the reported cases.

    Worldmeter discusses some of this here - https://www.worldometers.info/coronavirus/coronavirus-death-rate/#correct

    Their text is below

    The correct formula, therefore, would appear to be:

    CFR = deaths at day.x / cases at day.x-{T}
    (where T = average time period from case confirmation to death)

    This would constitute a fair attempt to use values for cases and deaths belonging to the same group of patients.

    One issue can be that of determining whether there is enough data to estimate T with any precision, but it is certainly not T = 0 (what is implicitly used when applying the formula current deaths / current cases to determine CFR during an ongoing outbreak).

    Let's take, for example, the data at the end of February 8, 2020: 813 deaths (cumulative total) and 37,552 cases (cumulative total) worldwide.

    If we use the formula (deaths / cases) we get:

    813 / 37,552 = 2.2% CFR (flawed formula).

    With a conservative estimate of T = 7 days as the average period from case confirmation to death, we would correct the above formula by using February 1 cumulative cases, which were 14,381, in the denominator:

    Feb. 8 deaths / Feb. 1 cases = 813 / 14,381 = 5.7% CFR (correct formula, and estimating T=7).

    T could be estimated by simply looking at the value of (current total deaths + current total recovered) and pair it with a case total in the past that has the same value. For the above formula, the matching dates would be January 26/27, providing an estimate for T of 12 to 13 days. This method of estimating T uses the same logic of the following method, and therefore will yield the same result.

    An alternative method, which has the advantage of not having to estimate a variable, and that is mentioned in the American Journal of Epidemiology study cited previously as a simple method that nevertheless could work reasonably well if the hazards of death and recovery at any time t measured from admission to the hospital, conditional on an event occurring at time t, are proportional, would be to use the formula:
     
    #23     Nov 1, 2020
  4. Cuddles

    Cuddles

    ??
    upload_2020-11-1_12-32-25.png
     
    #24     Nov 1, 2020
  5. gwb-trading

    gwb-trading

    Yes... and Worldmeter covers all of this in their detailed discussion. Since cases are normally only closes 8 weeks or more after they are reported... while in the midst of a pandemic it makes sense to use reported cases to get a more accurate and current CFR figure --- the real question is the time delay T for deaths (if used) to get a accurate numerator in the equation.

    Note that Worldmeter does not call this 4% figure the CFR --- it is the percentage of deaths divided by closed cases.
     
    #25     Nov 1, 2020