title: Variances and uncertainties of the sample laboratory-to-laboratory variance (S(L)2) and standard deviation (S(L)) associated with an interlaboratory study.
abstract: The validation process for an analytical method usually employs an interlaboratory study conducted as a balanced completely randomized model involving a specified number of randomly chosen laboratories, each analyzing a specified number of randomly allocated replicates. For such studies, formulas to obtain approximate unbiased estimates of the variance and uncertainty of the sample laboratory-to-laboratory (lab-to-lab) STD (S(L)) have been developed primarily to account for the uncertainty of S(L) when there is a need to develop an uncertainty budget that includes the uncertainty of S(L). For the sake of completeness on this topic, formulas to estimate the variance and uncertainty of the sample lab-to-lab variance (S(L)2) were also developed. In some cases, it was necessary to derive the formulas based on an approximate distribution for S(L)2.
authors.affiliation: U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Food Defense, Communication and Emergency Response, Division of Public Health and Biostatistics, 5100 Paint Branch Pkwy, College Park, MD 20740-3835, USA. fdmc5100@yahoo.com
authors.forename: Foster D
authors.initials: FD
authors.lastname: McClure
authors.forename: Jung K
authors.initials: JK
authors.lastname: Lee
mesh_terms: D000465:Algorithms; D015982:Bias; D007753:Laboratories / Q000592:standards*; D015233:Models, Statistical; D011897:Random Allocation; D015203:Reproducibility of Results; D012107:Research Design / Q000706:statistics & numerical data*; D035501:Uncertainty; D054928:Validation Studies as Topic