Aggregate verification data across the directory, with caveats posts 61–75

I would put moderate confidence on the mainstream reading of aggregate verification data and no more. That is not scepticism for its own sake; it is where the sourcing actually stops.

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.

This is the sort of thing that ought to be settled and apparently is not.

Post #60 is the version of this I will quote in future. One addition.

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.

Thank you — that answers what I came here to find out.

My experience of aggregate verification data contradicts the reply above. I am posting it as a data point rather than as a refutation, because one person's experience is exactly that.

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

That is the practical version. The rigorous version is longer and says the same thing.

Confirming post #65 from a second method, which matters more than confirming it from a second person.

Answering the aggregate verification data question as asked, then the question I think is meant. As asked: yes, with the qualification below. As meant: it depends on how the first measurement was taken.

I had written a reply contradicting post #66 and deleted it. Here is what survived.

Nobody has said the unglamorous part of aggregate verification data yet, so: most of the variation is explained by things that are boring to write about and easy to check.

This follows post #68 rather than contradicting it.

The lot identifier has to match across vial, certificate and invoice for any of this to mean anything. It is the floor and it is worth checking every time.

Worth separating two things that post #66 runs together.

Before the thread moves on from aggregate verification data — 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.

Trying to state the aggregate verification data position in a way that someone who disagrees would recognise as fair, because I do not think the version in this thread passes that test.

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.

Not disagreeing with anyone above, just adding the bit I keep having to look up.

I read post #69 twice before replying, because I had assumed the opposite.

An update on my earlier aggregate verification data post: the pattern held for another six weeks and then stopped, which I did not predict and cannot explain.

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

Somebody will have a better source than mine, and I hope they post it.