1、Designation:D277721Standard Practice forDetermination of Precision and Bias of Applicable TestMethods of Committee D19 on Water1This standard is issued under the fixed designation D2777;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision
2、,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 establishes uniform standards for estimat-ing and expressing the precision and bias of applicabl
3、e testmethods for Committee D19 on Water.Statements of precisionand bias in test methods are required by the Form and Style forASTM Standards,“Section A21.Precision and Bias(Manda-tory).”In principle,all test methods are covered by thispractice.However,the variability equations provided in thisstand
4、ard are applicable only to test methods that yield continu-ous function values.1.2 Except as specified in 1.4,1.5,and 1.6,this practicerequires the task group proposing a new test method to carryout a collaborative study from which statements for precision(overall and single-operator standard-deviat
5、ion estimates)andbias can be developed.This practice provides general guidanceto task groups in planning and conducting such determinationsof precision and bias.1.3 This practice requires that a task group making asubstantive revision to a test method also perform a limited-scale collaborative study
6、(known as a comparability study)to evaluate the effect of the revision on the precision and biasstatement.This practice provides guidance to task groups forconducting such limited-scale collaborative studies.Examplesof substantive modifications may include,but are not limitedto,changes in mandatory
7、or allowable instrumentation,reagents,reaction times,etc.1.3.1 Changes to applicable water matrices in the Scope ofa method may constitute a substantive modification under thisprovision.Only matrices that have been evaluated in anapproved collaborative study may be listed in the Scope of amethod.It
8、is recognized that the term“matrix”is generallyvague.Terms specifying matrix types can cover significantlydifferent chemical constituents,unless the matrix is synthe-sized to be of a standardized makeup.Substitute Wastewater(Practice D5905)is one such defined matrix.For purposes ofthis practice,the
9、importance of this requirement is to assist theuser of a D19 standard in determining the applicability of themethod to their samples.Evaluated matrices should be de-scribed with as much detail as possible to minimize misappli-cation.1.3.2 A methods concentration-range extension that isdeemed to meri
10、t additional collaborative testing(even withouta method modification that would otherwise be consideredsubstantive)shall require a full collaborative study,as de-scribed in 7.1 through 7.5,but only at concentrations represen-tative of the extended range.Note that such a collaborativestudy could invo
11、lve as little as a single concentration study ina single reproducible matrix.1.3.3 Whether a revision to a test method includes substan-tive modification shall be determined by consensus of theCommittee.1.4 If a full-scale collaborative study is not technicallyfeasible,because of the nature of the t
12、est method or instabilityof samples,the most complete collaborative study that istechnically feasible shall be conducted to provide the bestpossible limited basis for estimating the overall and single-operator standard deviations.In some situations,an intermedi-ate collaborative study as described i
13、n Guide D7847 mayprovide an appropriate approach.It is recognized that theremay be circumstances when even a limited collaborative studyis not feasible.Any collaborative study plan that does not meetall the requirements spelled out in this practice will require areview and recommendation by the Resu
14、lts Advisor and anapproval by the D19 Technical Operations Section of theExecutive Subcommittee.1.4.1 Examples of acceptable studies are the local-areaintermediate studies conducted by Subcommittee D19.24 onmicrobiological methods because of inherent sample perish-ability.Such intermediate collabora
15、tive studies meet the samedegrees of freedom and participant requirements as full col-laborative studies.They involve six or more completelyindependent local-area analysts who can begin analysis ofuniform samples at an agreed upon time.Guide D7847 canprovide guidance to the task group,the Results Ad
16、visor,andthe Technical Operations Section of the Executive Subcommit-tee of Committee D19 on the appropriate design of an1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.02 on Quality Systems,Specification,and Statistics.Current edition approved Dec.15,2021.Published June 2022.Originallyapproved in 1969.Last previous edition approved in 2013 as D2777 13.DOI:10.1520/D2777-21.Copyright ASTM International,100 Barr Harbor Dri
