This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
The question underneath reporting a discrepancy 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.
Building on post #29 rather than restating it.
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.
That has been true for the cases I have seen and I have not seen many.
Marking my uncertainty on reporting a discrepancy explicitly. I am confident about the direction, much less confident about the size, and not confident at all that it generalises past the case in the first post.
If someone has run reporting a discrepancy properly I would rather read that than my own reconstruction of it. Posting mine only because the thread has gone quiet.
Where I part company with post #33, and it is a narrow parting.
Reports of ordinary results are more valuable than reports of remarkable ones, precisely because only the remarkable ones get posted elsewhere.
Same conclusion as the reply above, reached differently, which is mildly reassuring.
Post #33 is the version of this I will quote in future. One addition.
Agreed on reporting a discrepancy, with one qualification that I think matters. The reasoning holds for the case as described. Change the starting assumption and it does not, and the starting assumption is the part nobody states.
That matches what I have seen, for whatever a single anecdote is worth.
Do not adjust a reported figure. Post what the laboratory said and put your interpretation in a separate sentence.
That has held every time I have looked, which is not the same as always.
Picking up post #38: that is the part I would want checked first.
I read the earlier replies on reporting a discrepancy 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.
A note on how reporting a discrepancy gets discussed rather than on reporting a discrepancy itself: the confident posts get the replies and the careful ones get ignored, and the careful ones have been right more often.
Post #44 describes the usual case. This is about the unusual one.
Reporting rather than recommending, on reporting a discrepancy. What happened is above. Whether it should have is a different question and not one I am qualified to answer.
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.
That is the shape of it. The detail is where I would expect to be corrected.
Reports of ordinary results are more valuable than reports of remarkable ones, precisely because only the remarkable ones get posted elsewhere.
The general case is well covered; this is the awkward specific one.
Answering the question post #49 raises rather than the one it answers.
Reframing reporting a discrepancy slightly, because I think the disagreement is about the question rather than the answer. If the question is "does it happen", yes. If it is "how often", nobody here knows.
Taking post #51 at face value and following it one step further.
Do not adjust a reported figure. Post what the laboratory said and put your interpretation in a separate sentence.
Second this, and I would have said it less carefully.
Worth separating two things that post #51 runs together.
Adding the boring version of reporting a discrepancy, because the interesting version keeps getting posted and the boring one is usually right.
Check the ordinary explanations, in order, and stop when one of them accounts for what you are seeing. Most of the time the second one does.
This follows post #55 rather than contradicting it.
Reports of ordinary results are more valuable than reports of remarkable ones, precisely because only the remarkable ones get posted elsewhere.
Two things can be true about reporting a discrepancy 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.
I keep a log for reporting a discrepancy specifically because my memory of it turned out to be systematically wrong in one direction. Six weeks of notes cost nothing and settled it.
On post #55 — agreed on the reasoning, with one qualification.
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.
Fine by me. I had wanted a stronger conclusion and there is not one available.