What a purity-only report leaves out posts 31–60

Everything in post #27 holds. The case it does not cover is the one I have.

The question underneath purity-only is usually "how would I tell?" rather than "what is true?", and that one has a method attached to it.

Write down what you would expect to see under each hypothesis before you collect anything. If they predict the same observation, collecting it will not help.

I would put moderate confidence on the mainstream reading of purity-only 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 where my knowledge stops and I would rather mark the edge than blur it.

Seconded. It reads as careful rather than confident, which is the right register.

My experience of purity-only 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.

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

I am describing what is, rather than arguing for what should be.

What I would want before treating purity-only as settled: the method, the sample, and whether anyone tried to find the opposite result. Two of the three are usually missing.

Building on post #35 rather than restating it.

Reading back through the purity-only threads from last year, the same three questions come up every time and only one of them has ever been answered properly. That seems like a documentation gap rather than a knowledge gap.

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

Worth checking against a second source before it gets quoted onward.

Building on post #39 rather than restating it.

Purity-only 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.

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.

Source for the purity-only figure, since it was asked for. It is in the discussion rather than the abstract, which is why the version circulating is stronger than the paper is.

Reading the surrounding paragraph is worth the two minutes. The authors are more careful than their summarisers.

Everything in post #42 holds. The case it does not cover is the one I have.

I disagree with the framing of purity-only above, and I think it is a substantive disagreement rather than a terminological one. Setting out why, so it can be checked.

The reasoning depends on an assumption that is doing a lot of work and is never stated. If the assumption holds, the conclusion follows. I do not think it holds generally.