AOAC Method Validation (August 29, 2018)

RSD i

(Intermediate Precision)

Background X Some method developers have been submitting method validation manuscripts containing data for repeatability (RSDr) that is actually intermediate precision (RSDi). X Traditional RSDr data consists of replicate analysis to a common sample by a single analysis, using a single instrument, over a short duration (a day). X RSDi is an extension of RSDr in that multiple analysts using multiple instruments over multiple days analyze a common sample. Presumably the variability of a RSDi greater than the variability of a RSDr.

RSD i

(Intermediate Precision)

Background

X Typically, AOAC SMPRs set a maximum for RSDr, but are silent on RSDi.

X Some method developers and Expert Review Panel members have asked for a separate RSDi tolerance in AOAC SMPRs so that method developers who choose to collect RSDi data, which presumably will be greater than RSDr, are not “penalized”.