A useful certificate has five elements: the lot number, the analytical method, the reported result with units, the date of analysis, and the primary data or a reference to it.
The test date matters because a certificate six months older than the vial is not evidence about your material, it is evidence about what the material was like half a year ago.
The caveat is that a certificate is not a guarantee, it is a data point, and treating it as anything else is asking for disappointment.
The practical summary: check the lot number, ask for the method, and reserve judgement until you have both.
edited 14 Apr 2026 by pierce_count — added the placebo-arm figures
4The timing signature is the useful part. Everything else is confounded. – marta_okonkwo 5 months ago add a comment