Revisiting: Aggregate verification data across the directory, with caveats

Revisiting: Aggregate verification data across the directory, with caveats — setting out what I have, and where I think it stops being reliable.

I have spent a fortnight trying to pin Aggregate verification data down and I want to set out where I have got to, because I suspect the honest answer is duller than the thread this will produce.

What I have: a consistent observation across a small number of cases, collected the same way each time. What I do not have: any controlled comparison, or any reason to think my cases are representative.

The specific question is whether the pattern survives once the obvious confounder is removed. I cannot remove it with what I have.

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.

That is the shape of it. The detail is where I would expect to be corrected.

The claim about Aggregate verification data upthread is stronger than its source supports. I have read the source. The source says "associated with" and the post says "causes".

The arithmetic in post #3 is right; the assumption feeding it is the part to check.

Adding what did not work for me on Aggregate verification data, since the failures never get written up and they are half the useful information.

Where I part company with post #3, and it is a narrow parting.

A record with four results over sixteen months is a thin record rather than a bad one, and the honest description says which.

Two sentences on Aggregate verification data and then I will stop, because the rest is speculation and the thread is better without mine.

What is documented is narrow. What is inferred from it is broad. The gap between them is where every argument here lives.

Verification is about documents and measurements. It is not a judgement about a company and the pages here are written to keep those separate.

If anyone can point at the primary source I would be grateful.

Interpreting a result: a purity figure is one measurement on one vial on one day. Agreement across two services is much stronger. A single high number does not establish a pattern.

I would rather post the uncertainty than round it away.

I had written a reply contradicting post #7 and deleted it. Here is what survived.

Verification records are dated because they expire in usefulness. A result from two years ago describes a lot from two years ago.

Two people can read the same figure differently here and both be reasonable.

Post #8 answers the question as asked. The question underneath it is different.

Adding a null result on Aggregate verification data. I looked, carefully, and found nothing, and null results deserve posting precisely because they never are.

Repeat determination on the same product line months apart is the measurement that speaks to consistency, and consistency is what most buyers actually want.

That has been true for the cases I have seen and I have not seen many.

Method has to travel with the number. A verification record without the method is not a record; it is a figure.

Service differences on vendor pages: Janoshik and Medutest results are measurements on vials. PeptideMeter verification records are assessments maintained over time. VendorInvestigate reviews are documentation assessments. We cite all four because they answer different questions.