This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
Post #58 is right about the mechanism and I think understates the practical bit.
Two claims get bundled together under Blind submission and they need separating. The descriptive one — this is what was observed — is usually well supported. The causal one — this is why — usually is not.
Almost every disagreement in threads like this one dissolves once you say which of the two you are making.
That is consistent with mine, for whatever one more account is worth.
What would change my mind on Blind submission is a second dataset collected by someone with no stake in the first. Until then I hold it loosely and I would rather say so than pretend to more.
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.
I am not the right person to answer the follow-up to this.
Confirming post #63 from a second method, which matters more than confirming it from a second person.
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.
One case, stated as one case.
I would rather this thread reach "we do not know" about Blind submission than reach a confident answer that nobody can support when asked.
Blind sampling: submitting without the laboratory or seller knowing the source removes the two easiest ways for a result to be shaped: selective submission and selective reporting. The extra effort is worth it.
This is the sort of thing the wiki should carry and currently does not.
Where the Blind submission reasoning breaks down for me is the step from the group result to the individual case. That step is almost never argued for.
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.
Reading this Blind submission thread as someone who came in with a fixed view: the third and seventh replies moved me and the confident ones did not.
Following this. I have the same question and no better information than the first post.
Repeat determination on the same product line months apart is the measurement that speaks to consistency, and consistency is what most buyers actually want.
A definition problem is doing most of the work in this Blind submission discussion. Once the term is pinned down I suspect the disagreement mostly goes away and what is left is small.
The record shows what was measured. Everything beyond that is inference and this site tries to keep the line visible.
Someone should write this up properly, and it should probably not be me.
The arithmetic in post #80 is right; the assumption feeding it is the part to check.
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.
Written in the hope of being told what I have missed.
I would be cautious about generalising from the Blind submission example above. It is a good example. It is one example.
Post #82 put the caveat in the right place and I want to underline it.
A record with four results over sixteen months is a thin record rather than a bad one, and the honest description says which.
Take it as a starting point and not as a specification.
Noted, and I have changed what I was going to do on the strength of it.
Everything in post #82 holds. The case it does not cover is the one I have.
On Blind submission, I would rather understate and be corrected upward than overstate and be quoted. That is a house style here and it is a good one.
The claim about Blind submission upthread is stronger than its source supports. I have read the source. The source says "associated with" and the post says "causes".
Blind submission has a well-known answer and a correct answer, and the interesting work is establishing that they are the same. Nobody has done that here yet.