Before comparing a brochure figure, record its definition and unit. The same term can describe different measurement methods; ask your supplier for a technical document stating the method and conditions.
For volume, distinguish external dimensions, internal volume, and usable space after fittings are installed. For weight or carrying capacity, ask what components are included and how the product is arranged.
For a holding-time, insulation, or performance claim, check starting conditions, load, openings, measurement position, tolerance, and test report. Do not fill in missing details with your own assumptions.
A standard reference, test result, and conformity document are different forms of evidence. Verify the document's scope, issuer, validity information, and match to the model; leave missing evidence visible in the comparison table.