title: Handling false negatives, false positives and reporting limits in analytical proficiency tests.
abstract: The Harmonised Protocol on proficiency testing produced by ISO, IUPAC and AOAC International recommends that participants' results on interval or ratio scales are converted to z-scores for assessment. When proficiency tests are conducted with materials that contain little or no analyte (simulating real conditions in residue analysis) scheme organisers have reported difficulty with applying the z-scoring system when false negatives and false positives occur. This paper concludes that the z-scoring system is adaptable without change to false negatives and positives, although a degree of statistical expertise is called for.
authors.affiliation: Analytical Division, Royal Society of Chemistry, Piccadilly, London, UK.
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000592:standards*; D004350:Drug Residues / Q000032:analysis*; D005188:False Negative Reactions; D005189:False Positive Reactions; D007753:Laboratories / Q000592:standards*