title: The measurand problem in breath alcohol testing.
abstract: Proper interpretation of forensic measurements can be critical to the administration of justice. Breath alcohol testing is commonly relied upon to measure the concentration of alcohol in breath or, indirectly, in blood. The concentration sought constitutes the "quantity intended to be measured," referred to as the measurand. Although breath tests always probe the same physical quantity, their measurand is dictated by statute and varies between jurisdictions. Thus, identical numerical values obtained from tests in disparate jurisdictions may refer to different quantities and may not indicate the relevant statutory measurand. This can lead to misinterpretation of results, referred to as the "measurand problem." We first illustrate the concept of the measurand. Thereafter, the measurand problem is illustrated through application of Hlastala's breath test paradigm and Gullberg's work on breath test uncertainty. It is shown that where the measurand is not properly accounted for, conclusions based upon breath test evidence are undermined.
authors: Attorney at Law, 8105 NE 140th Pl, Kirkland, WA, 98034.
authors: Ted
authors: T
authors: Vosk
authors: A Robert W
authors: AR
authors: Forrest
authors: Ashley
authors: A
authors: Emery
authors: Lauren D
authors: LD
authors: McLane
mesh_terms: D001944:Breath Tests / Q000379:methods*; D002492:Central Nervous System Depressants / Q000032:analysis*; D000431:Ethanol / Q000032:analysis*; D053593:Forensic Toxicology / Q000331:legislation & jurisprudence; D006801:Humans; D008954:Models, Biological; D015813:Substance Abuse Detection / Q000331:legislation & jurisprudence* / Q000379:methods
chemical_list: D002492:Central Nervous System Depressants; D000431:Ethanol
keywords: forensic breath alcohol tests; forensic metrology; forensic science; legislation; measurand; measurement uncertainty