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

Here4money said:
CFR is best estimated using closed cases
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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:
 
gwb-trading said:
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:
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upload_2020-11-1_12-32-25.png
 
Here4money said:
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View attachment 242943
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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.
 
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