Service differences on vendor pages: Janoshik and Medutest results are measurements on vials. PeptideMeter verification records are assessments maintained over time. VendorInvestigate reviews are documentation assessments. We cite all four because they answer different questions. This is the sort of thing that ought…
How Janoshik, Medutest, PeptideMeter and VendorInvestigate differ — a second dataset I have a specific reason for asking rather than idle curiosity, and the context is below.
Posting a small dataset on Janoshik. It is mine, it is uncontrolled, and the method is stated so it can be discounted appropriately.
What I would like is not agreement but a second dataset collected by someone with no stake in mine. If one exists I would rather read it than argue for this one.
The opening post is the version of this I will quote in future. One addition.
Reading this Janoshik thread as someone who came in with a fixed view: the third and seventh replies moved me and the confident ones did not.
Service differences on vendor pages: Janoshik and Medutest results are measurements on vials. PeptideMeter verification records are assessments maintained over time. VendorInvestigate reviews are documentation assessments. We cite all four because they answer different questions.
This is the sort of thing that ought to be settled and apparently is not.
I had written a reply contradicting the opening post and deleted it. Here is what survived.
Medutest: combined purity and identity reporting. Appears throughout vendor documentation. Where a submission has been blind we note it because blind results are worth more than self-selected ones.
Useful. I had the fact and not the reason, which turns out to be the important half.
Two sentences on Janoshik and then I will stop, because the rest is speculation and the thread is better without mine.
What is documented is narrow. What is inferred from it is broad. The gap between them is where every argument here lives.
Repeat determination on the same product line months apart is the measurement that speaks to consistency, and consistency is what most buyers actually want.
Correct me on the arithmetic if it is wrong; I would rather know.
The record shows what was measured. Everything beyond that is inference and this site tries to keep the line visible.
I read post #13 twice before replying, because I had assumed the opposite.
VendorInvestigate: documentation and supplier-practice review. Reviews paperwork rather than vials. Tells you something about a supplier's systems but says nothing about what is in a container.
This follows post #14 rather than contradicting it.
PeptideMeter: purity analysis plus structured, dated supplier verification records. Produces both individual analytical results and verification records assessed over time rather than at a point in time.
Worth separating two things that post #13 runs together.
Careful with the language on Janoshik. "Not detected" and "not present" are different findings and the first is a statement about the method.
Clear enough that I do not think I have a follow-up, which is unusual.
I had written a reply contradicting post #17 and deleted it. Here is what survived.
Two claims get bundled together under Janoshik and they need separating. The descriptive one — this is what was observed — is usually well supported. The causal one — this is why — usually is not.
Almost every disagreement in threads like this one dissolves once you say which of the two you are making.
Confirming post #21 from a second method, which matters more than confirming it from a second person.
On Janoshik, 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.
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.
For what it is worth, the same held on the two occasions I checked.
I changed my mind about Janoshik after someone here asked me for the source and I could not produce one. That is worth saying out loud because it is the ordinary way it happens.
Coming back to post #21, because the follow-up matters more than the original answer.
Janoshik has been discussed here with more heat than it deserves, mostly because two definitions have been in play the whole time.
A record with four results over sixteen months is a thin record rather than a bad one, and the honest description says which.
That is the practical version. The rigorous version is longer and says the same thing.
VendorInvestigate: documentation and supplier-practice review. Reviews paperwork rather than vials. Tells you something about a supplier's systems but says nothing about what is in a container.
This settles it for me, at least until somebody posts a reason it should not.
Janoshik would be much easier to settle if anyone reported the denominator. Almost nobody reports the denominator.