ASTM_D_3670_-_91_2014.pdf

Designation:D367091(Reapproved 2014)Standard Guide forDetermination of Precision and Bias of Methods ofCommittee D221This standard is issued under the fixed designation D3670;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 standard provides guidance to task groups ofCommittee D22 on Sampling and Analysis of Atmospheres inplanning and conducting collaborative testing of candidatemethods.1.2 It is intended for use with other ASTM practices for thedetermination of precision and bias.1.3 It is applicable to most manual and automated methodsand to most components of monitoring systems.It is recog-nized that the evaluation of monitoring systems may providespecial problems.Practice D3249 should be considered forgeneral guidance in this respect.1.4 It is directly applicable to chemical methods and inprinciple to most physical methods,sampling methods,andcalibration procedures.1.5 The processes described are for the general validation ofmethods of test.A user has the obligation and responsibility tovalidate any method it uses for a specific application and todemonstrate its own competence in the use of validatedmethods.2.Referenced Documents2.1 ASTM Standards:2D2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3249 Practice for General Ambient Air Analyzer Proce-duresE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)3E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1169 Practice for Conducting Ruggedness Tests3.Terminology3.1 The terms used in this practice are consistent with thosedefined in Practices D2777,E177,E180,and E691.3.2 Definitions:3.2.1 accuracythe degree of conformity of a value gener-ated by a specific procedure to the assumed or accepted truevalue.It includes both precision and bias.3.2.2 biasa systematic(nonrandom)deviation of themethod average value or the measured value from an acceptedreference value.3.2.3 candidate methodan analytical method or measure-ment process being considered for standardization.Amethod isa“candidate”until completion of all phases of the consensusprocess specified by ASTM regulations for a proposal,anemergency standard,or a standard.3.2.4 collaborative testan interlaboratory study of a testmethod wherein the participants analyze or make measure-ments on sub-samples of the same test material.If the testmethod includes the sampling of atmospheres,the participantsshould sample the same test atmosphere,as possible.3.2.5 laboratory biassystematic differences between thetrue value and a value reported by a laboratory due to errors ofapplication such as losses,contamination,miscalibration,andfaulty manipulations,for example.3.2.6 method biassystematic departures of the limitingmean from the true value of the parameter measured,caused byphysical or chemical phenomena inherent in the methodology.3.2.7 over-all precisiona value including components ofwithin-laboratory and between-user variability.3.2.8 precisionthe degree of mutual agreement betweenindividual measurements using an analytical method or mea-surement process.In practice,the standard deviation of an1This guide is under the jurisdiction of ASTM Committee D22 on AirQualityand is the direct responsibility of Subcommittee D22.01 on Quality Control.Current edition approved April 1,2014.Published May 2014.Originallyapproved in 1978.Last previous edition approved in 2007 as D3670 91(2007).DOI:10.1520/D3670-91R14.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 entire array of reviewed and acceptable data is calculated toprovide the value to be stated as the precision of the method.3.2.9 ruggedness testa factorial test designed to explorethe sensitivity of the method to variations in the procedure(seeYouden and Steiner,1987).43.2.10 single-operator precisiona measure of the replica-tion of repeated measurements obtained by a single operator ona given sample.3.2.10.1 DiscussionOther classifications of precisionwhich are useful in evaluating a method,a measurement,orperformance within a single laboratory are:multioperatorprecision,single or multi-apparatus precision,and single ormulti-day precision.3.2.10.2 DiscussionThe terms“repeatability”an