4 ms·

I don't think we have any statistical tests that will give us any kind of certainty with a 1/14 result. At best you could assume it fits the expected value (ma

I don't think we have any statistical tests that will give us any kind of certainty with a 1/14 result. At best you could assume it fits the expected value (maximum likelihood) of a binomial distribution[0], which gives us a 35% chance that the next sample of 14 such people would have no cases at all. 0. https://www.wolframalpha.com/input/?i=binomial+distribution+n%3D14+p+%3D1%2F14 https://www.wolframalpha.com/input/?i=binomial+distribution+...

contravariant 6y ago
You're not quite thinking in the right direction. No matter the statistical model a 1/14 result, is absolute evidence against there being no infections at all. The problem lies with the test itself, which might have an unknown false positive rate. Although in this case we're basically looking at what I understand to be the gold standard in RNA/DNA evidence, combined with matching symptoms. Also apparently they had 2 separate teams testing the samples using different methodology, so we've got at least a decent amount of confidence that something is going on with that sample, although it doesn't rule out systematic bias.
- icegreentea2 6y ago
  Yes. It's possible (I can't put a number on how likely) that the sample was mishandled and contamination introduced. Depending at what stage this occurred, this could affect all future tests of the sample. Ideally they are able to follow up with serological tests against the specific patient. While a positive carries no information (might have gotten COVID in the intervening time), a negative would point to some sort of sample contamination. This isn't a knock against their skill or their competence. Sometimes shit just happens. Certainly if this is true, I'd be very interested in how this changes the nature of our models of the virus.
  - skwb 6y ago
    Yeah, but for IRB reasons, you may not be able to contact the patient. IMHO I would prefer this (potentially) imperfect short communication being out in the scientific world now than a more perfect communication requiring several more months.
    - SiempreViernes 6y ago
      If this turns out to be a false positive from contamination, how many man-month do you estimate will be wasted on making models that don't describe reality before the error is caught?
  - Jabbles 6y ago
    If it is possible to sequence the sample they would be able to confirm that it came from a very early branch of the genetic tree, rather than one introduced at a much later stage.

contravariant 6y ago

You're not quite thinking in the right direction. No matter the statistical model a 1/14 result, is absolute evidence against there being no infections at all. The problem lies with the test itself, which might have an unknown false positive rate. Although in this case we're basically looking at what I understand to be the gold standard in RNA/DNA evidence, combined with matching symptoms. Also apparently they had 2 separate teams testing the samples using different methodology, so we've got at least a decent amount of confidence that something is going on with that sample, although it doesn't rule out systematic bias.

icegreentea2 6y ago
Yes. It's possible (I can't put a number on how likely) that the sample was mishandled and contamination introduced. Depending at what stage this occurred, this could affect all future tests of the sample. Ideally they are able to follow up with serological tests against the specific patient. While a positive carries no information (might have gotten COVID in the intervening time), a negative would point to some sort of sample contamination. This isn't a knock against their skill or their competence. Sometimes shit just happens. Certainly if this is true, I'd be very interested in how this changes the nature of our models of the virus.
- skwb 6y ago
  Yeah, but for IRB reasons, you may not be able to contact the patient. IMHO I would prefer this (potentially) imperfect short communication being out in the scientific world now than a more perfect communication requiring several more months.
  - SiempreViernes 6y ago
    If this turns out to be a false positive from contamination, how many man-month do you estimate will be wasted on making models that don't describe reality before the error is caught?
- Jabbles 6y ago
  If it is possible to sequence the sample they would be able to confirm that it came from a very early branch of the genetic tree, rather than one introduced at a much later stage.