Revisiting: Aggregate verification data across the directory, with caveats

Revisiting: Aggregate verification data across the directory, with caveats — setting out what I have, and where I think it stops being reliable.

I would like to talk about documentation quality as a signal, separately from product quality.

Across the certificates I have collected, the variation in what is disclosed is much larger than the variation in the purity figures. Some name the analytical procedure; some give a number and a signature.

My hypothesis is that disclosure correlates with process control, and I would like to know whether the people who audit paperwork for a living think that is naive.

Repeat testing: if you want to verify the same lot a second time, testing with a different service strengthens the conclusion. Testing with the same service verifies reproducibility but uses the same method.

Picking up post #8: that is the part I would want checked first.

Blind sampling: submitting without the laboratory or seller knowing the source removes the two easiest ways for a result to be shaped: selective submission and selective reporting. The extra effort is worth it.

Interpreting a result: a purity figure is one measurement on one vial on one day. Agreement across two services is much stronger. A single high number does not establish a pattern.

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.