[2026 update] What a purity-only report leaves out posts 91–104

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.

I had written a reply contradicting post #91 and deleted it. Here is what survived.

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 uncertainty is in the assumption, not in the calculation.

Picking up post #92: that is the part I would want checked first.

On purity-only: the maintained page in the documentation commons covers the general case with citations and a review date, which is more reliable than any reply here including this one.

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.

Post #92 is right about the mechanism and I think understates the practical bit.

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 is a description of practice, not a recommendation of it.

Coming back to post #94, because the follow-up matters more than the original answer.

Worth separating purity-only as a question about the compound from purity-only as a question about the documentation. They get answered by different people and only one of them is answerable here.

Acknowledging rather than arguing. The reasoning holds as far as I can follow it.

The confident answers on purity-only and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category.

The record shows what was measured. Everything beyond that is inference and this site tries to keep the line visible.

It reads as pedantry until the day it does not.

Taking purity-only seriously for a moment rather than deflecting: the honest position is that the community has observations and no controlled comparison, and those two things support very different sentences.

If you are new and reading this thread for the answer to purity-only: the answer is conditional, the conditions are in the third reply, and the rest of the thread is worth skipping.

Coming back to post #100, because the follow-up matters more than the original 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.

Worth stating the null on purity-only before we explain it: the observation may be nothing. That possibility deserves a sentence and usually does not get one.

My position on purity-only is current rather than settled. I have revised it once already and I expect to again, so treat it accordingly.