ASTM_E_2782_-_11e1.pdf

Designation:E2782111An American National StandardStandard Guide forMeasurement Systems Analysis(MSA)1This standard is issued under the fixed designation E2782;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.1NOTEEditorial corrections were made throughout in May 2014.1.Scope1.1 This guide presents terminology,concepts,and selectedmethods and formulas useful for measurement systems analy-sis(MSA).Measurement systems analysis may be broadlydescribed as a body of theory and methodology that applies tothe non-destructive measurement of the physical properties ofmanufactured objects.1.2 UnitsThe system of units for this guide is not speci-fied.Dimensional quantities in the guide are presented only asillustrations of calculation methods and are not binding onproducts or test methods treated.1.3 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 MethodsE456 Terminology Relating to Quality and StatisticsE2586 Practice for Calculating and Using Basic StatisticsE2587 Practice for Use of Control Charts in StatisticalProcess Control3.Terminology3.1 Definitions:3.1.1 Unless otherwise noted,terms relating to quality andstatistics are defined in Terminology E456.3.1.2 accepted reference value,na value that serves as anagreed-upon reference for comparison,and which is derivedas:(1)a theoretical or established value,based on scientificprinciples,(2)an assigned or certified value,based on experi-mental work of some national or international organization,or(3)a consensus or certified value,based on collaborativeexperimental work under the auspices of a scientific orengineering group.E1773.1.3 calibration,nprocess of establishing a relationshipbetween a measurement device and a known standard value(s).3.1.4 gage,ndevice used as part of the measurementprocess to obtain a measurement result.3.1.5 measurement process,nprocess used to assign anumber to a property of an object or other physical entity.3.1.5.1 DiscussionThe term“measurement system”issometimes used in place of measurement process.(See 3.1.7.)3.1.6 measurement result,nnumber assigned to a propertyof an object or other physical entity being measured.3.1.6.1 DiscussionThe word“measurement”is used in thesame sense as measurement result.3.1.7 measurement system,nthe collection of hardware,software,procedures and methods,human effort,environmen-tal conditions,associated devices,and the objects that aremeasured for the purpose of producing a measurement.3.1.8 measurement systems analysis(MSA),nany of anumber of specialized methods useful for studying a measure-ment system and its properties.3.2 Definitions of Terms Specific to This Standard:3.2.1 appraiser,nthe person who uses a gage or measure-ment system.3.2.2 discrimination ratio,nstatistical ratio calculatedfrom the statistics from a gage R&R study that measures thenumber of 97%confidence intervals,constructed from gageR&R variation,that fit within six standard deviations of trueobject variation.3.2.3 distinct product categories,nalternate meaning ofthe discrimination ratio.3.2.4 gage consistency,nconstancy of repeatability vari-ance over a period of time.3.2.4.1 DiscussionConsistency means that the variationwithin measurements of the same object(or group of objects)under the same conditions by the same appraiser behaves in a1This guide is under the jurisdiction of ASTM Committee E11 on Quality andStatistics and is the direct responsibility of Subcommittee E11.20 on Test MethodEvaluation and Quality Control.Current edition approved Nov.15,2011.Published February 2012.DOI:10.1520/E2782-11E01.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 state of statistical control as judged,for example,using acontrol chart.See Practice E2587.3.2.5 gage performance curve,ncurve that shows theprobability of gage acceptance of an object given its real valueor the probability that an objects real measure meets arequirement given the measurement of the object.3.2.6 gage R&R,ncombined effect of gage repeatabilityand reproducibility.3.2.7 gage resolution,ndegree to which a gage candiscriminate between differing objects.3.2.7.1 DiscussionThe smallest difference between twoobjects that