Robert Chung wrote:
Kurgan Gringioni wrote:
Seriously, what's a potential systemic bias in this case? I'm
curious
what that may be.

I emphasize that I don't know about this particular case but, in
other
particular cases I've examined, systematic bias can arise because
tests
were done in the same place by the same people with the same
equipment.
This type of bias sometimes happens when there are a very limited
number
of places where something is performed, or a limited number of
examiners
who were all trained in the same place. Sometimes people see what
they
expect to see (we could name some rbr'ers who fall into that
category);
sometimes this happens innocently. Here's a kinda innocent way that
things
can get biased: suppose, for example, 1) blood doping is pretty
evenly
spread across the peloton; 2) experts at the technique are better at
recognizing blood doping than novices; and 3) when a case happens to
be
sensitive it gets shunted up to an expert (this appears to be what
happened at the Olympics, and Dick Pound suggested that Hamilton's
Vuelta
tests were scrutinized exactly because of the Oly results). Now
suppose
samples from teammates of the suspected blood doper are considered to
be
sensitive, and thus also get shunted to experts (it needn't be the
same
expert, just to another expert who has a higher detection rate than a
novice). You would tend to see more doping than the overall rate
based on
the experts' analyses, but you'd also see less doping than the
overall
rate based on the novices' analyses.



Dumbass -

I don't see how the above would make it more likely that two roomates
would be the only two "false positives".

thanks,

K. Gringioni.