caa a22 4500 605465576 CHVBK 20210128100303.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00769-015-1162-z doi (NATIONALLICENCE)springer-10.1007/s00769-015-1162-z Ellison Stephen LGC Limited, Teddington, Middlesex, UK aut Homogeneity studies and ISO Guide 35:2006 [Elektronische Daten] [Stephen Ellison] Homogeneity assessment of reference materials is discussed with particular reference to the recommendations given in ISO Guide 35. It is suggested that Guide 35 could be improved by the addition of a wider range of experimental designs, and by using statistical power calculations to improve the recommendations for design of experiments for homogeneity assessment. It is further shown that the present recommended allowance for possible inhomogeneity uncertainty in the absence of a significant between-bottle effect does not have a sound statistical basis and is considerably smaller than an accurate upper 95% confidence limit for the between-unit term. Alternatives are considered, including the use of a more accurate (and usually much larger) calculation of possible between-unit variance, post hoc power calculation, and the simple use of the calculated between-unit variance coupled with increased emphasis on effective experimentation to limit the risk of underestimation. Recommendations for improved guidance are made. Springer-Verlag Berlin Heidelberg, 2015 Reference material certification nationallicence Homogeneity studies nationallicence ISO Guide 35 nationallicence Accreditation and Quality Assurance Springer Berlin Heidelberg 20/6(2015-12-01), 519-528 0949-1775 20:6<519 2015 20 769 https://doi.org/10.1007/s00769-015-1162-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00769-015-1162-z text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Ellison Stephen LGC Limited, Teddington, Middlesex, UK aut NATIONALLICENCE 773 0- Accreditation and Quality Assurance Springer Berlin Heidelberg 20/6(2015-12-01), 519-528 0949-1775 20:6<519 2015 20 769