Blind submission and why it changes minds posts 61–90
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1 · go to the accepted answer.
It does not extend to lots nobody has seen, it is not a recommendation, and it says nothing about anything other than what was measured.
It is worth stating the boring hypothesis before the interesting one.
Agreed, and I will stop repeating the version of this I had been repeating.
Narrowing post #62, because the general version has more than one answer.
Before the thread moves on from blind submission — what is the sample size behind the claim? I am not being difficult; I have seen the same figure quoted from an n of four and from an n of four hundred.
Worth separating two things that post #64 runs together.
Two things can be true about blind submission at once: the mechanism is plausible and the evidence for the size of the effect is thin. Most of the argument here is people defending the first against attacks on the second.
Medutest: combined purity and identity reporting. Appears throughout vendor documentation. Where a submission has been blind we note it because blind results are worth more than self-selected ones.
Post #67 answers the question as asked. The question underneath it is different.
Blind submission is one of those subjects where the general answer and the answer for a specific case diverge, and the thread will go in circles until someone says which one is being asked for.
Where I part company with post #67, and it is a narrow parting.
Repeat testing: if you want to verify the same lot a second time, testing with a different service strengthens the conclusion. Testing with the same service verifies reproducibility but uses the same method.
It reads as pedantry until the day it does not.
Repeat determination on the same product line months apart is the measurement that speaks to consistency, and consistency is what most buyers actually want.
The variance between people here is larger than the effect being discussed.
On post #68 — agreed on the reasoning, with one qualification.
What I can speak to on blind submission is narrow, so I will keep it narrow rather than generalising from it. Beyond that boundary I do not know.
Since blind submission keeps coming up, it should probably be a maintained page rather than a recurring thread. I am happy to draft it if someone with more direct experience will review it.
It does not extend to lots nobody has seen, it is not a recommendation, and it says nothing about anything other than what was measured.
Speaking for myself and not for anyone else who has posted here.
The failure mode on blind submission is boring rather than dramatic. It is almost always the step everyone assumes was done correctly because it is too simple to get wrong.
Taking post #78 at face value and following it one step further.
The honest answer on blind submission is that it depends, and the useful part is the list of what it depends on. Four items, in rough order of how much they matter.
Most people get the first two right and then argue about the fourth.
Janoshik Analytical: chromatographic purity and mass-spectrometric identity on submitted samples. Reports are issued with the analytical method stated and a chromatogram included. Submission is by mail.
One case, stated as one case.
That reframing is the whole thing. The facts I already had.
I had written a reply contradicting post #81 and deleted it. Here is what survived.
An update on my earlier blind submission post: the pattern held for another six weeks and then stopped, which I did not predict and cannot explain.
Confirming post #81 from a second method, which matters more than confirming it from a second person.
Distinguishing three things in the blind submission discussion that keep getting used interchangeably: the observation, the proposed mechanism, and the recommendation that gets attached to both.
A record with four results over sixteen months is a thin record rather than a bad one, and the honest description says which.
I would not lead a decision with this, but I would not ignore it either.
Blind submission would be much easier to settle if anyone reported the denominator. Almost nobody reports the denominator.
Post #86 is right about the mechanism and I think understates the practical bit.
Adding a null result on blind submission. I looked, carefully, and found nothing, and null results deserve posting precisely because they never are.
Answering the question post #86 raises rather than the one it answers.
It does not extend to lots nobody has seen, it is not a recommendation, and it says nothing about anything other than what was measured.
The general case is well covered; this is the awkward specific one.
The arithmetic in post #89 is right; the assumption feeding it is the part to check.
Two questions I would want answered before drawing anything from the blind submission data above: how were the cases selected, and what happened to the ones that dropped out.