how do you separate batch variance from supplier variance
#test-results 2025-06-22
Sunday31 messages6 participantstimes are UTC
Highlights from this day
log the boring ones
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a single sample tells you about a single vial. that is genuinely all it tells you
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
if you are testing to settle an argument you will not settle it with n of 1
one data point
unrelated but my sheet has 4 lots from Homopeptide with a spread under a point, which is tight
do the results in this channel skew because people test when suspicious
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thats not great
attach the pdf
test it again
whats the underfill rate people are actually seeing
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how do you post a result so it is actually useful to somebody in a year
sorry to jump in is anyone tracking results over time in a way they would share
update on the earlier thing one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
quick one does a bad result on one lot condemn the whole supplier
log the boring results too. a channel that only records failures produces a false picture
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sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
nice result
for the archive do you test every order or sample it
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
a result without a lot number and a purchase date is an anecdote with a pdf attached
i told QSC about a result they would not have liked and they did not argue. credit where it is due
unrelated but how many lots do you need before you can say anything about a supplier
when did you buy it
thats within range
ok so i had a result i am fairly sure was a handling error on my side and i logged it as such
selection bias
a point or two between the certificate and an independent result is inside what two labs disagree by
which lab
the widest spread in my data is about 2.6 percentage points across five lots from one supplier, your mileage will differ
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