How do I compare WXT and WWB on lead time to South Africa?

What I am working with: WXT · WWB · South Africa.

Both of these get recommended confidently by different people, which suggests neither is obviously right.

My constraints are cost, measurement resolution and how much handling I am prepared to do — in roughly that order.

What is the actual trade-off, and does it matter at the scale I am working at?

The short version: same compound, same laboratory, same method, ideally same week — otherwise you are comparing laboratories rather than suppliers.

Submitting to different laboratories introduces a method difference that commonly exceeds the supplier difference. Gradient slope alone can move a reported purity figure by a per cent in either direction.

The part that matters: content is the more discriminating measurement than purity for supplier comparison, because purity clusters tightly among competent suppliers and content does not.

Use a fixed documentation checklist rather than an impression.

Ratings on this site are ours alone and are deliberately not reconciled with anyone else's.

Lead time and lane behaviour are supplier properties too and are easier to compare than analytical ones, because they need no laboratory at all.

To compare properly: order the same compound at the same nominal strength from each supplier, submit all samples to the same laboratory in the same submission if possible, and ask for the same test set on each.

Content assay results across the published datasets vary considerably more between suppliers than purity does, which makes content the more discriminating axis.

Name the laboratory and the dates or the comparison cannot be reproduced.

Put another way, this is the question where methodology matters more than the conclusion.

Publish the method with the result. A comparison without the laboratory named and the submission dates given is not reproducible by anyone.

No supplier on this site pays for its position, and the storefront links are marked nofollow and sponsored.

One laboratory, one method, one submission. Otherwise it is not a comparison.

edited 9 May 2024 by a_lindgren — reworded for clarity after a comment

Answer first: comparing suppliers is only meaningful if the comparison holds the laboratory, the method and the compound constant, and most published comparisons hold none of them.

Sample size matters. One order each is an anecdote about six vials; three orders each over a year is the beginning of a comparison.

The ratings on this site are a community opinion average on a ten-point scale and are not reconciled with any other community's figures.

The caveat is that a comparison is a snapshot of the lots compared, and lots change.

Compare content, not purity. Purity clusters and content does not.

edited 24 May 2024 by Dr_Malik_Osei — added the citation requested in comments