Measurements quality evaluation

When designing and evaluating an analytical method, we usually make three separate considerations of experimental error. First, before beginning an analysis, errors associated with each measurement are evaluated to ensure that their cumulative effect will not limit the utility of the analysis. Errors known or believed to affect the result can then be minimized. Second, during the analysis the measurement process is monitored, ensuring that it remains under control. Finally, at the end of the analysis the quality of the measurements and the result are evaluated and compared with the original design criteria. This chapter is an introduction to the sources and evaluation of errors in analytical measurements, the effect of measurement error on the result of an analysis, and the statistical analysis of data. 

Quality, unlike beauty is not simply in the eye of the beholder. Quality may be assessed, measured and evaluated, to be expressed in terms such as good-poor, acceptable-unacceptable. Quality may also improve or deteriorate depending on the efforts, enthusiasm and expertise of the analysts and the environment in which the work is carried out. 

Over the past decade, a major trend has been the development of the use of proficiency testing (PT) or evaluation materials (Fox 2000). PT materials are a type of reference material, which aid in assessment of analytical laboratory measurement quality. There will be an increased use of such materials as part of laboratory accreditation programs and other new quality assurance efforts, including internal audits. At the same time, a number of providers have used PT schemes to produce a form of RM intended to meet the ever-growing need for RMs required for routine QC use (Jenks 1995,1997). 

Quality of food products and the ability to guarantee the quality of a food product is becoming increasingly important in a global economy where there are multiple sources for the food product. This need to measure, control and guarantee quality has resulted in an emphasis to develop more analytical techniques/sensors to measure a product for both external and internal quality. Consider quality evaluation of fresh fruits and vegetables. 

Originally, SFI was developed to measure quality of soils of cacao fields (Alvim and Rosand 1974). Moran et al. (2000) extended its use in forest soils in the humid tropics, where the climate is classified as Am or Af (Koppen 1931). Recently, Doi and Sakurai (2004) found the applicability of SFI and SEF to evaluating soil quality in the SERS. 

IS ISO (1995) ISO 11734. Water Quality -Evaluation of the Ultimate" Anaerobic Biodegradability of Organic Compounds in Digested Sludge - Method by Measurement of the Biogas Production, International Organization for Standardization,... 

ISO] International Organization for Standardization. 2006a. Water quality — evaluation of genotoxicity by measurement of micronuclei — Part 1 evaluation of genotoxicity using amphibian larvae. ISO/FDIS 21427-1 2006(E). 

The compositional analysis is an essential part of the quality evaluation of petroleum-derived fuels. The concentration of different compound types such as paraffin, isoparaffin, olefin, naphthene and aromatic are routinely determined by gas chromatography (FIONA analysis), and can be rapidly measured by proton NMR spectroscopy. 

ISO 11734 (1995). Water quality - Evaluation of the ultimate anaerobic biodegradability of organic compounds in digested sludge - Method by measurement of the biogas production... 

The principal criteria presently being used to measure quality of coconut oil are free fatty acids content and color. In addition, sensory evaluation through taste and odor of oil serves to confirm the acceptability of the product. 

US-EPA, Quality Assurance Unit Staff, Office of Environmental Measurement and Evaluation, Immunoassay Guidelines for Planning Environmental Projects, US-EPA, New England, 1996, pp. 45. 

In contrast to how quality is measured and evaluated, satisfaction is specific to the individual and is based on the perceptions and judgments of individuals. It follows, then, that patient satisfaction is an individual s judgment about the extent to which a healthcare product or service provides a pleasurable level of consumption-related fulfillment. In the recent literature, satisfaction has been conceptualized in four ways 1) performance evaluation 2) disconfirmation of expectations 3) affect-based assessment and 4) equity-based assessment (Table 1). 

From the beginning of its monitoring programme, HELCOM took measures to evaluate and improve the recommended methods by intercalibrations between the different partners (HELCOM, 1983 Niemi et al., 1985 HELCOM, 1991). The HELCOM Phytoplankton Expert Group (PEG) takes care of quality assurance in phytoplankton methodology. It published a manual on biovolumes and size-classes of phytoplankton species in the Baltic Sea (Olenina et al., 2006), which is based on the species checklist of Hallfors (2004). We strictly use the species names given by Hallfors (2004). The autotrophic ciliate Mesodinium rubrum Myrionecta rubra) is counted to the phytoplankton. 

Kaplan RM, Bush JW. Health-related quality of life measurement for evaluation research and policy analysis. Health Psychol 1982 1 61-80. 

Gilmer, L., Caico, C. A., Sherrick, J. J., Mueller, G. R., and Loos, K. R. "Flare Waste Gas Flow and Composition Measurement Methodologies Evaluation Document." Report prepared for the Texas Commission on Environmental Quality, 2006. 

Any testing campaign requires measurements to evaluate the thermal oxidizer s performance. The set of instrumentation used for the test should be carefully chosen. Each instrument will have certain capabilities and limitations that will affect the quality of the test data. The instrument that is used needs to be capable of making measurements over the entire testing range. Furthermore, the instrument needs to have suitable accuracy for the expected measurement range. The durability and maintenance requirements of the instruments will also affect the selection. 

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