Third-party testing (revision 2)

Third-party testing is the analysis of a material by a laboratory that is independent of the supplier and of the manufacturer, commissioned by the purchaser and reported to the purchaser. It is distinguished from a supplier's own certificate of analysis not by the analytical methods used, which may be identical, but by who paid for the work and who receives the result.^[1]

The distinction matters because the incentive structure differs. A supplier commissioning analysis of its own material controls which sample is submitted, whether an unfavourable result is published, and how the result is described. A purchaser commissioning analysis of material already received controls none of those things but is testing a sample of unknown representativeness.^[2]