Posting this under the heading it deserves: Reconciling a supplier certificate with an independent result Everything below is what sits behind that.
Reconciling a supplier certificate — I have the observation and I do not trust my interpretation of it, so I am posting the observation and holding the interpretation back.
Numbers, method and the conditions under which they were collected are below. Interpret them however they warrant.
Date the submission as well as the result. Turnaround is part of what people want to know and it disappears if only one date is recorded.
Dosing and purity: a vial that is 99% pure might contain 80% of its label claim if the other mass is water, counter-ion, and excipient. Purity and content are different. Both matter for different reasons.
I keep a log of this specifically because memory is unreliable about it.
On post #2 — agreed on the reasoning, with one qualification.
Two things can be true about Reconciling a supplier certificate at once: the mechanism is plausible and the evidence for the size of the effect is thin. Most of the argument here is people defending the first against attacks on the second.
Post #4 answers the question as asked. The question underneath it is different.
Say in advance that you will post the result whatever it says. It costs nothing and it is the difference between a record and a collection of the interesting cases.
I would want the raw data before agreeing with my own summary of it.
Where you have no independent result, a documentation report is still worth filing: what the certificate contained, what it omitted, and how fast a request was answered.
The confident answers on Reconciling a supplier certificate and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category.
Reading back through, this was answered upthread and I missed it. My fault.
Everything in post #6 holds. The case it does not cover is the one I have.
Source for the Reconciling a supplier certificate 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.
On post #10 — agreed on the reasoning, with one qualification.
Report the certificate figure alongside the independent one. The comparison is the point and it is the part most often omitted.
Temporal patterns: if results from a supplier were good two years ago but have deteriorated recently, that is information. If they have been consistent over years, that is also information.
Helpful, and short, which on this subject is harder than long.
Post #12 is right about the mechanism and I think understates the practical bit.
Since Reconciling a supplier certificate keeps coming up, it should probably be a maintained page rather than a recurring thread. I am happy to draft it if someone with more direct experience will review it.
This follows post #14 rather than contradicting it.
Pattern across lots: a single result is a data point. Three or four results from the same supplier showing a consistent pattern becomes a record worth discussing. Two results that disagree might just be measurement variation.
Reporting rather than recommending, on Reconciling a supplier certificate. What happened is above. Whether it should have is a different question and not one I am qualified to answer.
I read the earlier replies on Reconciling a supplier certificate twice before writing this, because I had assumed the opposite and wanted to be sure I was disagreeing with what was said rather than what I expected.
The arithmetic in post #18 is right; the assumption feeding it is the part to check.
Disputed records: when a result disagreed and was not explained, the record says disputed and stays that way. We do not remove inconvenient history; we document it.
I have changed my mind on this once already, so take it as current rather than settled.
I think the Reconciling a supplier certificate question is answerable and has not been answered, which is a more optimistic position than most of this thread.
I read post #20 twice before replying, because I had assumed the opposite.
Recording a reorder result against the original is one of the highest-value contributions here, because consistency over time is what a single result cannot show.
Taking post #22 at face value and following it one step further.
Comparing your result to somebody else's on a different lot is not a comparison of suppliers. Lot is the unit and it should be in every report.
Multiple services on one lot: agreement across two independent laboratories is stronger than a high number from one. Our vendor pages deliberately mix services for that reason.
Not the whole picture, but the part of it I can speak to.
The format we ask for is compound, lot, testing service, method as reported, result, and the certificate figure for the same lot. A report missing any of those goes to the discussion rather than the record.
Noting that I have skin in this question and have tried to discount for it.
On Reconciling a supplier certificate, the part that usually goes wrong is that the question is asked as though it has one answer. It has a range, and the width of the range is the interesting bit.
If you can post the two or three numbers you are working from, several people here will check the arithmetic rather than argue about the conclusion.
Post #28 put the caveat in the right place and I want to underline it.
Structured report format: compound, lot, independent testing service, method as reported, result, and the certificate figure for the same lot. One lot is one lot. It becomes a pattern at three or four, and it becomes a disputed record when asked and not explained.