Complementary use of inter-laboratory certification study data

The agreed purpose of an inter-laboratory certification study is to characterise a certified reference material (CRM). In addition to this, any (successful) certification study may also be utilised as a laboratory/method performance study by the participants. The intention of this note is to emphasise the complementary use of certification study data by the participants of the certification study and to explain the options involved. On this occasion, an apparent paradox arising in the interpretation of certification study data is resolved. The procedures for bias correction and estimation of bias-related uncertainty contributions discussed on this occasion are, however, generally applicable to normal CRM use.