NOMENCLATURE OF INTERLABORATORY ANALYTICAL STUDIES (IUPAC RECOMMENDATIONS 1994)

There are three major types of interlaboratory studies in which a group of laboratories analyzes identical test portions from a homogeneous, stable test sample. Each type is characterized by a self-defining designation according to its purpose: (1) Method-performance study.-A study in which all laboratories follow the same written protocol and use the same test method to measure a property (usually concentration of an analyte) in order to assess the performance parameters of a method. (2) Laboratory-performance study.-A study in which laboratories use the method of their choice to measure a property in order to assess the performance of the laboratory or analyst, usually to evaluate or improve performance. (3) Material-certification study.-A study that assigns a reference value to a characteristic in the test material, usually with a stated uncertainty, using the ''best'' laboratories and the least-biased methods. Vague terms such as ''round-robins,'' ''intercalibrations,'' ''ring tests,'' etc., should not be used.