Ascertainment bias and statistical-methodology critique
The argument
Critics argue that early case-finding favoured market-linked and market-proximate patients and that the spatial test used does not validly establish non-random clustering, since a population-density null would be rejected around almost any central-Wuhan landmark. On this view the recorded concentration around the market reflects how cases were found and where people live, not a genuine market-centred cluster.
Does it work?
- Does it follow?
- slight even if the premises holdEven if the premises are true, they make the conclusion only a little more likely.constitution →
- Do the premises hold?
- 2 inconclusive
Granting both premises, the argument does more damage to the inference that the market was the epicentre than to the descriptive claim that the recorded cases lie around the market. A flawed significance test leaves the observed locations where they were. Ascertainment bias would erode the descriptive claim, as a picture of true early infection, only if it were severe enough to create the pattern. Both biased ascertainment and invalidity of the test are currently inconclusive.
Premises
- InconclusiveThe evidence and argument have been examined and do not come down on either side.constitution →Early COVID-19 case ascertainment was biased toward cases linked to the Huanan market
- InconclusiveThe evidence and argument have been examined and do not come down on either side.constitution →A spatial statistical test does not validly establish non-random clustering of early COVID-19 cases around the Huanan Market
Where it is made
Passages where sources make, criticize or mention this argument. They record where it appears, not how strong it is, and none has precedence over another.
No source is recorded as making it.