ASTM_E_2489_-_11.pdf

Designation:E248911An American National StandardStandard Practice forStatistical Analysis of One-Sample and Two-SampleInterlaboratory Proficiency Testing Programs1This standard is issued under the fixed designation E2489;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes methods for the statistical analy-sis of laboratory results obtained from interlaboratory profi-ciency testing programs.As in accordance with PracticeE1301,proficiency testing is the use of interlaboratory com-parisons for the determination of laboratory testing or mea-surement performance.Conversely,collaborative study(orcollaborative trial)is the use of interlaboratory comparisons forthe determination of the performance characteristics of amethod,as covered by Practice E691.1.1.1 Method A covers testing programs using single testresults obtained by testing a single sample(each laboratorysubmits a single test result).1.1.2 Method B covers testing programs using paired testresults obtained by testing two samples(each laboratorysubmits one test result for each of the two samples).The twosamples should be of the same material or two materials similarenough to have approximately the same degree of variation intest results.1.2 Methods A and B are applicable to proficiency testingprograms containing a minimum of 10 participating laborato-ries.1.3 The methods provide direction for assessing and catego-rizing the performance of individual laboratories based on therelative likelihood of occurrence of their test results,and fordetermining estimates of testing variation associated withrepeatability and reproducibility.Assumptions are that a ma-jority of the participating laboratories execute the test methodproperly and that samples are of sufficient homogeneity that thetesting results represent results obtained from each laboratorytesting essentially the same material.Each laboratory receivesthe same instructions or protocol.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE178 Practice for Dealing With Outlying ObservationsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1301 Guide for Proficiency Testing by InterlaboratoryComparisons(Withdrawn 2012)33.Terminology3.1 Definitions:3.1.1 The terminology defined in Terminology E456 appliesto this practice unless modified herein.3.1.2 collaborative study,ninterlaboratory study in whicheach laboratory uses the defined method of analysis to analyzeidentical portions of homogeneous materials to assess theperformance characteristics obtained for that method of analy-sis.43.1.3 collaborative trial,nsee collaborative study.3.1.4 interlaboratorycomparison,norganization,performance,and evaluation of tests on the same or similar testitems by two or more laboratories in accordance with prede-termined conditions.3.1.5 median,nmiddle value of a data set when the data isarranged in order of size or the average of the middle twovalues when there is an even number of items in the data set.3.1.6 outlier,nsee outlying observation.E1781This practice is under the jurisdiction ofASTM Committee E11 on Quality andStatistics and is the direct responsibility of Subcommittee E11.20 on Test MethodEvaluation and Quality Control.Current edition approved Oct.1,2011.Published October 2011.Originallyapproved in 2006.Last previous edition approved in 2006 as E2489 061.DOI:10.1520/E2489-11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Horwitz,W.,“Protocol for the Design,Conduct and Interpretation of Collab-orative Studies,”Pure and Applied Chemistry,Vol 60,No.6,1988,pp.855864.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.7 outlying observation,nobservation that appears todeviate markedly in value from other members of the sample inwhich it appears.E1783.1.8 proficiency testing,ndetermination of laboratorytesting performance by means of interlaboratory comparisons.3.1.9 repeatability standard deviation(Sr),nstandard de-viation of test results obtained under repeatability conditions.E1773.1.10