Attempts to include uncorrected bias in the measurement uncertainty

Synek, Václav

doi:10.1016/j.talanta.2004.07.038

Cited by 27 publications

(15 citation statements)

References 3 publications

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“…( 3) The systematic component of uncertainty, estimated as bias, can be added to the random component to give an estimate of the total relative expanded uncertainty of measurement (U' ). There is not a consensus on the best method for achieving this (Lyn et al 2003, Synek 2005), but the method described here is that described by Magnusson et al (2003) and Ramsey and Ellison (2007): (4) where:…”

Section: Methodsmentioning

confidence: 99%

Estimating and Optimising Analytical and Sampling Uncertainty in Environmental Investigations: Application and Evaluation

Boon

Taylor

2007

Geostandard Geoanalytic Res

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Measurements taken to characterise environmental contamination contain uncertainty, which is generated by both field sampling and chemical analyses. Recently devised techniques have been applied for the first time to estimate this uncertainty in the commercial monitoring and assessment of contaminated land. The uncertainty reduces the reliability of the classification of the land that is made following a site investigation. The possible misclassification of areas of land, as a result of measurement uncertainty, can lead to substantial financial penalties, resulting from litigation or unnecessary remediation. Previous studies have developed methods for the estimation and financial optimisation of measurement uncertainty. These methods have now been applied to a series of six contrasting site investigations, which were conducted by various commercial organisations. The previous uses of these sites included a gas works, a tin mine and railway sidings. The measurement uncertainty was successfully estimated for each of the six investigations, showing its applicability to a wide range of different sampling methods, such as trial pits, window sampling and augering. The measurement uncertainty ranged widely between sites from 25% to 158%, indicating that investigations can differ widely in their reliability. The field sampling tended to generate the largest component of the measurement uncertainty when compared to the contribution from the chemical analysis. The Optimised Contaminated Land Investigation (OCLI) method was applied to each site, with the initial aim of estimating the financial losses that could be incurred as a result of misclassifying the land, due to the uncertainty. It showed that the expectation of loss value per sampling location ranged from only £58 at one site to over £ 11 000 at another. The optimal level of uncertainty that produced the minimal financial loss was then calculated for each site. It provided a reduction in the expectation of loss for the whole site of over £ 10 000 at two of the sites and over £90 000 at two others. These findings demonstrate that implementing concepts of uncertainty can have practical benefits in environmental monitoring, and can enable improvements to be made in the quality of sampling and hence of measurements in general.

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Section: Methodsmentioning

confidence: 99%

Estimating and Optimising Analytical and Sampling Uncertainty in Environmental Investigations: Application and Evaluation

Boon

Taylor

2007

Geostandard Geoanalytic Res

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“…The QL uncertainty is frequently used in metrology for uncorrected systematic effects, e.g., in [6], [16], [19], [20], [23], [24] and indirectly for expanded uncertainties in [5], [17], [18]. The publications [6], [15], [19] even call the QL uncertainty a standard uncertainty, whereas [20], [23] avoid this on purpose.…”

Section: Usage and Terminologymentioning

confidence: 99%

About not Correcting for Systematic Effects

Klauenberg

Wübbeler

Elster

2019

Measurement Science Review

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In practice, measurement results are sometimes described by an estimate, which is not the best one as defined in the GUM. Such alternative estimates arise when the result of a measurement is not corrected for all systematic effects. No recommendation exists in the GUM for associating an uncertainty with an uncorrected estimate. A common choice in guidelines and in the literature is the uncertainty u\left( {y'} \right) = \sqrt {{u^2}\left( y \right) + {{\left( {y - y'} \right)}^2}} for an alternative estimate y′. It arises from the expected quadratic loss, on which, also in the GUM, the standard uncertainty u(y), and the best estimate y are based. However, such an uncertainty is not a standard uncertainty and we establish, it may not be used for uncertainty propagation. One consequence is, for example, that pairs (y′, u(y′)) are not to be used in calibration certificates.

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“…Данный подход позволяет установить, какой аналитический метод или система вносит больший вклад в общую MU. Для минимизации или устранения общей MU было разработано несколько более сложных расчетных методик [23,40,[63][64][65][66][67][68][69][70][71][72][73][74][75][76][77].…”

Section: переводная статьяunclassified