Specimen, proposed definition

The precision of a determination is defined as the concordance of a series of measurements of the same quantity (V3). The definition of precision includes the terms repeatability and reproducibility (Hll). Repeatability is a measure of the deviation of test results from their mean value, all determinations being carried out by one operator and without change of apparatus, where apparatus can be significant (Hll). For reproducibility in clinical chemistry the definition provided by Hughes (Hll) is not entirely satisfactory, and an alternative is proposed as follows reproducibility of a method is a measure of deviation of test results from their mean value, the determinations being carried out over a period of weeks or months, perhaps by different operators, the operators in no case knowing the identity of the analytical specimens that are being used to assess the continued quality of performance of the technique. 

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