What a documentation review can and cannot tell you posts 61–84

Adding thanks rather than a view. I do not have a view worth the space.

Adding a reference point for documentation review. Mine is a single case, collected without controls, and I am posting the method alongside it so it can be discounted appropriately.

The failure mode on documentation review is boring rather than dramatic. It is almost always the step everyone assumes was done correctly because it is too simple to get wrong.

Where I part company with post #60, and it is a narrow parting.

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.

One of those cases where knowing the mechanism does not help the decision.

Adding the measurement that post #62 says would settle it.

One more thing on documentation review that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice that, the apparent contradiction disappears.

Summarising the documentation review thread so far, since it is long and the answer is buried: the first reply has the method, the fourth has the correction to it, and the rest is people agreeing at length.

The four services answer different questions. A documentation review cannot tell you what is in a vial and a purity assay cannot tell you whether the records are internally consistent.

Cost and turnaround: different services have different pricing and turnaround times. Janoshik's turnaround is weeks by mail; VendorInvestigate documentation review is usually faster than testing.

Filing this under things that are true until someone shows me otherwise.

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

The general case is well covered; this is the awkward specific one.

On post #68 — agreed on the reasoning, with one qualification.

The most useful reply I ever got about documentation review was a request to state my units. It sounds like pedantry and it has saved me twice.

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

Reading it again, the caveat matters more than the finding.

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.

I had written a reply contradicting post #71 and deleted it. Here is what survived.

The useful distinction on documentation review is between what was measured and what was inferred from it. Both end up in the same sentence and only one of them has error bars.

Confirming post #71 from a second method, which matters more than confirming it from a second person.

Two claims get bundled together under documentation review 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.