Array ( [0] => {{short description|Science of measurement and its application}} [1] => {{distinguish|Meteorology}} [2] => {{good article}} {{Use British English|date=August 2021}} [3] => [4] => [[Image:NIST-4 Kibble balance.jpg|thumb|A [[Kibble balance]], which is used to measure [[weight]] via [[electric current]] and [[voltage]]. With this instrument, the measurement of mass is no longer dependent on a defined mass standard and is instead dependent on natural physical constants.]] [5] => [6] => '''Metrology''' is the scientific study of [[measurement]].{{cite web |title=''What is metrology?'' Celebration of the signing of the Metre Convention, World Metrology Day 2004 |url=http://www.bipm.org/en/convention/wmd/2004/ |publisher=BIPM |year=2004 |access-date=2018-02-21 |url-status=dead |archive-url=https://web.archive.org/web/20110927012931/http://www.bipm.org/en/convention/wmd/2004/ |archive-date=2011-09-27 }} It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the [[French Revolution]]'s political motivation to standardise units in France when a length standard taken from a natural source was proposed. This led to the creation of the decimal-based [[metric system]] in 1795, establishing a set of standards for other types of measurements. Several other countries adopted the metric system between 1795 and 1875; to ensure conformity between the countries, the [[Bureau International des Poids et Mesures]] (BIPM) was established by the [[Metre Convention]]. This has evolved into the [[International System of Units]] (SI) as a result of a resolution at the 11th [[General Conference on Weights and Measures]] (CGPM) in 1960.{{cite web|title=Resolution 12 of the 11th CGPM (1960)|url=http://www.bipm.org/en/CGPM/db/11/12/|publisher=Bureau International des Poids et Mesures|access-date=28 February 2017|url-status=live|archive-url=https://web.archive.org/web/20130514081801/http://www.bipm.org/en/CGPM/db/11/12/|archive-date=14 May 2013}} [7] => [8] => Metrology is divided into three basic overlapping activities:{{cite book [9] => |url = https://www.amazon.co.uk/Springer-Handbook-Metrology-Testing-ebook/dp/B007C5Z1M8#reader_B007C5Z1M8 [10] => |title = Springer Handbook of Metrology and Testing [11] => |at = 1.2.2 Categories of Metrology [12] => |editor1-first = Horst [13] => |editor1-last = Czichos [14] => |editor2-first = Leslie [15] => |editor2-last = Smith [16] => |edition = 2nd [17] => |year = 2011 [18] => |publisher = Springer [19] => |isbn = 978-3-642-16640-2 [20] => |url-status = dead [21] => |archive-url = https://web.archive.org/web/20130701061631/http://www.amazon.co.uk/Springer-Handbook-Metrology-Testing-ebook/dp/B007C5Z1M8#reader_B007C5Z1M8 [22] => |archive-date = 2013-07-01 [23] => }}{{cite book [24] => |url = http://resource.npl.co.uk/international_office/metrologyinshort.pdf [25] => |title = Metrology in Industry – The Key for Quality [26] => |publisher = [[International Society for Technology in Education|ISTE]] [27] => |author = Collège français de métrologie [French College of Metrology] [28] => |editor-first = Dominique [29] => |editor-last = Placko [30] => |year = 2006 [31] => |at = 2.4.1 Scope of legal metrology [32] => |isbn = 978-1-905209-51-4 [33] => |quote = ... any application of metrology may fall under the scope of legal metrology if regulations are applicable to all measuring methods and instruments, and in particular if quality control is supervised by the state. [34] => |url-status = live [35] => |archive-url = https://web.archive.org/web/20121023153656/http://resource.npl.co.uk/international_office/metrologyinshort.pdf [36] => |archive-date = 2012-10-23 [37] => }} [38] => * The definition of units of measurement [39] => * The realisation of these units of measurement in practice [40] => * Traceability—linking measurements made in practice to the reference standards [41] => These overlapping activities are used in varying degrees by the three basic sub-fields of metrology: [42] => * Scientific or fundamental metrology, concerned with the establishment of [[units of measurement]] [43] => * Applied, technical or industrial metrology—the application of measurement to manufacturing and other processes in society [44] => * Legal metrology, covering the regulation and statutory requirements for measuring instruments and methods of measurement [45] => In each country, a national measurement system (NMS) exists as a network of laboratories, [[calibration]] facilities and accreditation bodies which implement and maintain its metrology infrastructure.{{cite web|title=National Measurement System|url=http://www.npl.co.uk/nms|publisher=National Physical Laboratory|access-date=5 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170215230507/http://www.npl.co.uk/nms|archive-date=15 February 2017}} The NMS affects how measurements are made in a country and their recognition by the international community, which has a wide-ranging impact in its society (including economics, energy, environment, health, manufacturing, industry and consumer confidence). The effects of metrology on trade and economy are some of the easiest-observed societal impacts. To facilitate fair trade, there must be an agreed-upon system of measurement. [46] => [47] => =={{anchor|Historical development}}History== [48] => {{see also|History of measurement}} [49] => The ability to measure alone is insufficient; standardisation is crucial for measurements to be meaningful.{{cite web|title=History of Metrology|date=17 June 2016 |url=http://www.msc-conf.com/history-of-metrology/|publisher=Measurement Science Conference|access-date=28 February 2017|url-status=live|archive-url=https://web.archive.org/web/20170301094329/http://www.msc-conf.com/history-of-metrology/|archive-date=1 March 2017}} The first record of a permanent standard was in 2900 BC, when the [[Cubit#Ancient Egyptian royal cubit|royal Egyptian cubit]] was carved from black [[granite]]. The cubit was decreed to be the length of the Pharaoh's forearm plus the width of his hand, and replica standards were given to builders. The success of a standardised length for the building of [[Giza pyramid complex|the pyramids]] is indicated by the lengths of their bases differing by no more than 0.05 per cent. [50] => [51] => In China weights and measures had a semi religious meaning as it was used in the various crafts by the [[Kao Gong Ji|Artificers]] and in ritual utensils and is mentioned in the [[Book of Rites|book of rites]] along with the [[steelyard balance]] and other tools.{{Cite book |last=Confucius |url=https://books.google.com/books?id=cu3qDAAAQBAJ&q=book+of+rites |title=Delphi Collected Works of Confucius - Four Books and Five Classics of Confucianism (Illustrated) |date=2016-08-29 |publisher=Delphi Classics |isbn=978-1-78656-052-0 |language=en}} [52] => [53] => Other civilizations produced generally accepted measurement standards, with Roman and Greek architecture based on distinct systems of measurement. The collapse of the empires and the Dark Ages that followed lost much measurement knowledge and standardisation. Although local systems of measurement were common, comparability was difficult since many local systems were incompatible. England established the Assize of Measures to create standards for length measurements in 1196, and the 1215 [[Magna Carta]] included a section for the measurement of wine and beer.{{cite web|title=History of Length Measurement|url=http://www.npl.co.uk/educate-explore/posters/history-of-length-measurement/|publisher=National Physical Laboratory|access-date=28 February 2017|url-status=live|archive-url=https://web.archive.org/web/20170301094410/http://www.npl.co.uk/educate-explore/posters/history-of-length-measurement/|archive-date=1 March 2017}} [54] => [55] => Modern metrology has its roots in the [[French Revolution]]. With a political motivation to harmonise units throughout France, a length standard based on a natural source was proposed. In March 1791, the [[metre]] was defined.{{cite web|title=History of measurement – from metre to International System of Units (SI) |url=http://www.french-metrology.com/en/history/history-mesurement.asp |publisher=La metrologie francaise |access-date=28 February 2017 |url-status=dead |archive-url=https://web.archive.org/web/20110425025041/http://www.french-metrology.com/en/history/history-mesurement.asp |archive-date=25 April 2011 }} This led to the creation of the decimal-based [[metric system]] in 1795, establishing standards for other types of measurements. Several other countries adopted the metric system between 1795 and 1875; to ensure international conformity, the [[International Bureau of Weights and Measures]] ({{lang-fr|Bureau International des Poids et Mesures}}, or BIPM) was formed by the [[Metre Convention]]. Although the BIPM's original mission was to create international standards for units of measurement and relate them to national standards to ensure conformity, its scope has broadened to include electrical and [[Photometry (optics)|photometric]] units and [[ionizing radiation]] measurement standards. The metric system was modernised in 1960 with the creation of the [[International System of Units]] (SI) as a result of a resolution at the 11th [[General Conference on Weights and Measures]] ({{lang-fr|Conference Generale des Poids et Mesures}}, or CGPM). [56] => [57] => ==Subfields== [58] => Metrology is defined by the International Bureau of Weights and Measures (BIPM) as "the science of measurement, embracing both experimental and theoretical determinations at any level of uncertainty in any field of science and technology".{{cite web|title=What is metrology?|url=http://www.bipm.org/en/worldwide-metrology/|publisher=BIPM|access-date=23 February 2017|ref=BIPMDef|url-status=live|archive-url=https://web.archive.org/web/20170324081343/http://www.bipm.org/en/worldwide-metrology/|archive-date=24 March 2017}} It establishes a common understanding of units, crucial to human activity.{{cite book|url = http://resource.npl.co.uk/international_office/metrologyinshort.pdf|title = Metrology in Industry – The Key for Quality|publisher = [[International Society for Technology in Education|ISTE]]|author = Collège français de métrologie [French College of Metrology]|editor-first = Dominique|editor-last = Placko|year = 2006|isbn = 978-1-905209-51-4|url-status = live|archive-url = https://web.archive.org/web/20121023153656/http://resource.npl.co.uk/international_office/metrologyinshort.pdf|archive-date = 2012-10-23}} Metrology is a wide reaching field, but can be summarized through three basic activities: the definition of internationally accepted units of measurement, the realisation of these units of measurement in practice, and the application of chains of traceability (linking measurements to reference standards). These concepts apply in different degrees to metrology's three main fields: scientific metrology; applied, technical or industrial metrology, and legal metrology. [59] => [60] => ===Scientific metrology=== [61] => [62] => Scientific metrology is concerned with the establishment of units of measurement, the development of new measurement methods, the realisation of measurement standards, and the transfer of traceability from these standards to users in a society. This type of metrology is considered the top level of metrology which strives for the highest degree of accuracy. BIPM maintains a database of the metrological calibration and measurement capabilities of institutes around the world. These institutes, whose activities are peer-reviewed, provide the fundamental reference points for metrological traceability. In the area of measurement, BIPM has identified nine metrology areas, which are acoustics, electricity and magnetism, length, mass and related quantities, photometry and radiometry, ionizing radiation, time and frequency, thermometry, and chemistry.{{cite web |url = http://kcdb.bipm.org/appendixc/ |title = The BIPM key comparison database |publisher = BIPM |access-date = 26 Sep 2013 |url-status = live |archive-url = https://web.archive.org/web/20130928041400/http://kcdb.bipm.org/appendixc/ |archive-date = 2013-09-28 }} [63] => [64] => As of May 2019 no physical objects define the base units.[http://www.bipm.org/en/committees/cipm/meeting/105.html Decision CIPM/105-13 (October 2016)] The motivation in the change of the base units is to make the entire system derivable from [[physical constants]], which required the removal of the prototype kilogram as it is the last artefact the unit definitions depend on.{{cite web|title=New measurement will help redefine international unit of mass: Ahead of July 1 deadline, team makes its most precise measurement yet of Planck's constant|url=https://www.sciencedaily.com/releases/2017/07/170701103514.htm|website=ScienceDaily|access-date=23 March 2018|language=en}} Scientific metrology plays an important role in this redefinition of the units as precise measurements of the physical constants is required to have accurate definitions of the base units. To redefine the value of a kilogram without an artefact the value of the [[Planck constant]] must be known to twenty parts per billion.{{cite web|url = http://physicsworld.com/cws/article/indepth/2011/mar/22/metrology-in-the-balance|title = Metrology in the balance|first1 = Robert P.|last1 = Crease|access-date = 23 March 2018|work = Physics World|publisher = [[Institute of Physics]]|date = 22 March 2011}} Scientific metrology, through the development of the [[Kibble balance]] and the [[Avogadro project]], has produced a value of Planck constant with low enough uncertainty to allow for a redefinition of the kilogram. [65] => [66] => ===Applied, technical or industrial metrology=== [67] => [68] => Applied, technical or industrial metrology is concerned with the application of measurement to manufacturing and other processes and their use in society, ensuring the suitability of measurement instruments, their calibration and quality control. Producing good measurements is important in industry as it has an impact on the value and quality of the end product, and a 10–15% impact on production costs. Although the emphasis in this area of metrology is on the measurements themselves, traceability of the measuring-[[Measuring instrument|device]] calibration is necessary to ensure confidence in the measurement. Recognition of the metrological competence in industry can be achieved through mutual recognition agreements, accreditation, or peer review. Industrial metrology is important to a country's economic and industrial development, and the condition of a country's industrial-metrology program can indicate its economic status. [69] => [70] => ===Legal metrology=== [71] => [72] => Legal metrology "concerns activities which result from statutory requirements and concern measurement, [[Unit of measurement|units of measurement]], measuring instruments and methods of measurement and which are performed by competent bodies".{{cite book|title=International Vocabulary of Terms in Legal Metrology |url=http://www.oiml.org/publications/V/V001-ef00.pdf |publisher=OIML |year=2000 |page=7 |location=Paris |url-status=dead |archive-url=https://web.archive.org/web/20070928030048/http://www.oiml.org/publications/V/V001-ef00.pdf |archive-date=September 28, 2007 }} Such statutory requirements may arise from the need for protection of health, public safety, the environment, enabling taxation, protection of consumers and fair trade. The International Organization for Legal Metrology ([[OIML]]) was established to assist in harmonising regulations across national boundaries to ensure that legal requirements do not inhibit trade.{{cite book|last1=Sharp|first1=DeWayne|title=Measurement, instrumentation, and sensors handbook|date=2014|publisher=CRC Press, Inc.|location=Boca Raton|isbn=978-1-4398-4888-3|edition=Second}} This harmonisation ensures that certification of measuring devices in one country is compatible with another country's certification process, allowing the trade of the measuring devices and the products that rely on them. [[WELMEC]] was established in 1990 to promote cooperation in the field of legal metrology in the [[European Union]] and among [[European Free Trade Association]] (EFTA) member states.{{cite web|last1=WELMEC Secretariat|title=WELMEC An introduction|url=http://www.welmec.org/fileadmin/user_files/publications/WELMEC-general/WELMEC_Guide_1-2016_-_WELMEC_An_introduction.pdf|publisher=WELMEC|access-date=28 February 2017|url-status=live|archive-url=https://web.archive.org/web/20170228165051/http://www.welmec.org/fileadmin/user_files/publications/WELMEC-general/WELMEC_Guide_1-2016_-_WELMEC_An_introduction.pdf|archive-date=28 February 2017}} In the United States legal metrology is under the authority of the Office of Weights and Measures of [[National Institute of Standards and Technology]] (NIST), enforced by the individual states. [73] => [74] => == {{anchor|Fundamental concepts}}Concepts == [75] => === Definition of units === [76] => The [[International System of Units]] (SI) defines seven base units: [[length]], [[mass]], [[time]], [[electric current]], [[thermodynamic temperature]], [[amount of substance]], and [[luminous intensity]].{{cite web|title=SI base units|url=http://physics.nist.gov/cuu/Units/units.html|website=The NIST Reference on Constants, Units, and Uncertainty|publisher=National Institute of Standards and Technology|access-date=15 February 2017|url-status=live|archive-url=https://web.archive.org/web/20170119053614/http://physics.nist.gov/cuu/Units/units.html|archive-date=19 January 2017}} By convention, each of these units are considered to be mutually independent and can be constructed directly from their defining constants.{{SIbrochure9th}}{{rp|129}} All other SI units are constructed as products of powers of the seven base units.{{rp|129}} [77] => [78] => {| class="wikitable" [79] => |- [80] => |+SI base units and standards [81] => |- [82] => ! Base quantity !! Name !! Symbol !! Definition [83] => |- [84] => | Time || [[second]]|| s || The duration of 9192631770 periods of the radiation corresponding to the transition between the two [[Hyperfine structure|hyperfine]] levels of the [[ground state]] of the [[Isotopes of caesium#Caesium-133|caesium-133]] atom{{rp|130}} [85] => |- [86] => | Length || [[metre]]|| m || The length of the path travelled by light in a [[vacuum]] during a time interval of 1/299792458 of a second{{rp|131}} [87] => |- [88] => | Mass || [[kilogram]]|| kg || Defined ([[2019 redefinition of the SI base units|as of 2019]]) by "... taking the fixed numerical value of the [[Planck constant]], ''h'', to be {{val|fmt=commas|6.62607015|e=-34}} when expressed in the unit {{nowrap|J s}}, which is equal to {{nowrap|kg m2 s−1}} ..."{{rp|131}} [89] => |- [90] => | Electric current || [[ampere]]|| A || Defined (as of 2019) by "... taking the fixed numerical value of the [[elementary charge]], ''e'', to be {{val|fmt=commas|1.602176634|e=-19}} when expressed in the unit C, which is equal to {{nowrap|A s}} ..."{{rp|132}} [91] => |- [92] => | Thermodynamic temperature || [[kelvin]]|| K || Defined (as of 2019) by "... taking the fixed numerical value of the [[Boltzmann constant]], ''k'', to be {{val|fmt=commas|1.380649|e=-23}} when expressed in the unit {{nowrap|J K−1}}, which is equal to {{nowrap|kg m2 s−2 K−1}} ..."{{rp|133}} [93] => |- [94] => | Amount of substance || [[Mole (unit)|mole]] || mol || Contains (as of 2019) "... exactly {{val|fmt=commas|6.02214076|e=23}} elementary entities. This number is the fixed numerical value of the [[Avogadro constant]], ''N''A, when expressed in the unit mol−1 ..."{{rp|134}} [95] => |- [96] => | Luminous intensity || [[candela]] || cd || The luminous intensity, in a given direction, of a source emitting monochromatic radiation of a frequency of {{val|540|e=12|u=Hz}} with a radiant intensity in that direction of 1/683 watt per [[steradian]]{{rp|135}} [97] => |} [98] => [99] => Since the base units are the reference points for all measurements taken in SI units, if the reference value changed all prior measurements would be incorrect. Before 2019, if a piece of the international prototype of the kilogram had been snapped off, it would have still been defined as a kilogram; all previous measured values of a kilogram would be heavier.{{cite web|last1=Goldsmith|first1=Mike|title=A Beginner's Guide to Measurement|url=http://www.npl.co.uk/upload/pdf/NPL-Beginners-Guide-to-Measurement.pdf|publisher=National Physical Laboratory|access-date=16 February 2017|url-status=live|archive-url=https://web.archive.org/web/20170329111015/http://www.npl.co.uk/upload/pdf/NPL-Beginners-Guide-to-Measurement.pdf|archive-date=29 March 2017}} The importance of reproducible SI units has led the BIPM to complete the task of defining all SI base units in terms of [[physical constant]]s.{{cite web|title=On the future revision of the SI|url=http://www.bipm.org/en/measurement-units/rev-si/|publisher=Bureau International des Poids et Mesures|access-date=16 February 2017|url-status=dead|archive-url=https://web.archive.org/web/20170215111649/http://www.bipm.org/en/measurement-units/rev-si/|archive-date=15 February 2017}} [100] => [101] => By defining SI base units with respect to physical constants, and not artefacts or specific substances, they are realisable with a higher level of precision and reproducibility. As of the redefinition of the SI units on 20 May 2019 the [[kilogram]], [[ampere]], [[kelvin]], and [[Mole (unit)|mole]] are defined by setting exact numerical values for the [[Planck constant]] (''{{Math|h}}''), the [[elementary electric charge]] (''{{Math|e}}''), the [[Boltzmann constant]] (''{{Math|k}}''), and the [[Avogadro constant]] ({{Math|''N''A}}), respectively. The [[second]], [[metre]], and [[candela]] have previously been defined by physical constants (the [[caesium standard]] (Δ''ν''Cs), the [[speed of light]] (''{{Math|c}}''), and the [[luminous efficacy]] of {{val|540|e=12|u=Hz}} visible light radiation (''K''cd)), subject to correction to their present definitions. The new definitions aim to improve the SI without changing the size of any units, thus ensuring continuity with existing measurements. [102] => {{cite web [103] => |first=Michael|last=Kühne [104] => |title=Redefinition of the SI [105] => |url=http://www.its9.org/symposium_program.html#SI_Redefinition_Keynote_Abstract [106] => |work=Keynote address, ITS9 (Ninth International Temperature Symposium) [107] => |location=Los Angeles [108] => |access-date=1 March 2012|date=22 March 2012 [109] => |publisher=NIST [110] => |archive-url=https://web.archive.org/web/20130618064512/http://www.its9.org/symposium_program.html|archive-date=18 June 2013 [111] => |url-status=dead [112] => }}{{rp|123,128}} [113] => [114] => === Realisation of units === [115] => [116] => [[File:CGKilogram.jpg|thumb|alt=Computer-generated image of a small cylinder|Computer-generated image realising the international prototype of the kilogram (IPK), made from an alloy of 90-per cent platinum and 10-per cent iridium by weight]] [117] => The [[Realisation (metrology)|realisation]] of a unit of measure is its conversion into reality.{{OED|Realise}} Three possible methods of realisation are defined by the [[Joint Committee for Guides in Metrology#VIM: International vocabulary of metrology|international vocabulary of metrology]] (VIM): a physical realisation of the unit from its definition, a highly-reproducible measurement as a reproduction of the definition (such as the [[quantum Hall effect]] for the [[ohm]]), and the use of a material object as the measurement standard.{{cite book|title=International vocabulary of metrology—Basic and general concepts and associated terms (VIM)|date=2012|publisher=[[International Bureau of Weights and Measures]] on behalf of the Joint Committee for Guides in Metrology|page=46|edition=3rd|url=http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2012.pdf|access-date=1 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170317223139/http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2012.pdf|archive-date=17 March 2017}} [118] => [119] => === Standards === [120] => [121] => A [[Standard (metrology)|standard]] (or etalon) is an object, system, or experiment with a defined relationship to a unit of measurement of a physical quantity.Phillip Ostwald,Jairo Muñoz, ''Manufacturing Processes and Systems (9th Edition)''John Wiley & Sons, 1997 {{ISBN|978-0-471-04741-4}} page 616 Standards are the fundamental reference for a system of weights and measures by realising, preserving, or reproducing a unit against which measuring devices can be compared. There are three levels of standards in the hierarchy of metrology: primary, secondary, and working standards.{{cite book|last1=de Silva|first1=G. M. S|title=Basic Metrology for ISO 9000 Certification|date=2012|publisher=Routledge|location=Oxford|isbn=978-1-136-42720-6|pages=12–13|edition=Online-Ausg.|url=https://books.google.com/books?id=0akABAAAQBAJ&q=standards+hierarchy+metrology&pg=PA13|access-date=17 February 2017|url-status=live|archive-url=https://web.archive.org/web/20180227045858/https://books.google.com/books?id=0akABAAAQBAJ&pg=PA13&lpg=PA13&dq=standards+hierarchy+metrology&source=bl&ots=VMyW0MPSAL&sig=kziWErFv0k_dtc-EjphSzdVjV_8&hl=en&sa=X&ved=0ahUKEwjW3tzX_5fSAhVh6IMKHR2RCoUQ6AEIfTAU#v=onepage&q=standards%20hierarchy%20metrology&f=false|archive-date=27 February 2018}} Primary standards (the highest quality) do not reference any other standards. Secondary standards are calibrated with reference to a primary standard. Working standards, used to calibrate (or check) measuring instruments or other material measures, are calibrated with respect to secondary standards. The hierarchy preserves the quality of the higher standards. An example of a standard would be [[gauge blocks]] for length. A gauge block is a block of metal or ceramic with two opposing faces ground precisely flat and parallel, a precise distance apart.{{cite web|last1=Doiron|first1=Ted|last2=Beers|first2=John|title=The Gauge Block Handbook|url=https://www.nist.gov/sites/default/files/documents/calibrations/mono180.pdf|publisher=NIST|access-date=23 March 2018}} The length of the path of light in vacuum during a time interval of 1/299,792,458 of a second is embodied in an artefact standard such as a gauge block; this gauge block is then a primary standard which can be used to calibrate secondary standards through mechanical comparators.{{cite web|title=e-Handbook of Statistical Methods|url=https://www.itl.nist.gov/div898/handbook/mpc/section3/mpc312.htm|publisher=NIST/SEMATECH|access-date=23 March 2018}} [122] => [123] => === Traceability and calibration=== [124] => [125] => [[File:Traceability Pyramid.png|thumb|upright=1.5|alt=Pyramid illustrating the relationship between traceability and calibration|Metrology traceability pyramid]] [126] => Metrological traceability is defined as the "property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty".{{Cite book |url= http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf |title= International vocabulary of metrology – basic and general concepts and associated terms |publisher= Joint Committee on Guides for Metrology (JCGM) |year= 2008 |edition= 3 |url-status= dead |archive-url= https://web.archive.org/web/20110110120304/http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf |archive-date= 2011-01-10 |access-date= 2014-06-13 }} It permits the comparison of measurements, whether the result is compared to the previous result in the same laboratory, a measurement result a year ago, or to the result of a measurement performed anywhere else in the world.{{cite web|title=Metrological Traceability for Meteorology|url=https://www.wmo.int/pages/prog/www/IMOP/publications/Flyers/Traceability_flyer.pdf|publisher=World Meteorological Organization Commission for Instruments and Methods of Observation|access-date=2 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170317094030/http://www.wmo.int/pages/prog/www/IMOP/publications/Flyers/Traceability_flyer.pdf|archive-date=17 March 2017}} The chain of traceability allows any measurement to be referenced to higher levels of measurements back to the original definition of the unit. [127] => [128] => Traceability is most often obtained by [[calibration]], establishing the relationship between an indication on a measuring instrument (or secondary standard) and the value of the standard. A calibration is an operation that establishes a relation between a measurement standard with a known measurement uncertainty and the device that is being evaluated. The process will determine the measurement value and uncertainty of the device that is being calibrated and create a traceability link to the measurement standard. The four primary reasons for calibrations are to provide traceability, to ensure that the instrument (or standard) is consistent with other measurements, to determine accuracy, and to establish reliability. Traceability works as a pyramid, at the top level there is the international standards, at the next level national metrology institutes calibrate the primary standards through realisation of the units creating the traceability link from the primary standard and the unit definition. Through subsequent calibrations between national metrology institutes, calibration laboratories, and industry and testing laboratories the realisation of the unit definition is propagated down through the pyramid. The traceability chain works upwards from the bottom of the pyramid, where measurements done by industry and testing laboratories can be directly related to the unit definition at the top through the traceability chain created by calibration. [129] => [130] => === Uncertainty === [131] => [132] => [[Measurement uncertainty]] is a value associated with a measurement which expresses the spread of possible values associated with the [[measurand]]—a quantitative expression of the doubt existing in the measurement.{{cite book|title=Guide to the Evaluation of Measurement Uncertainty for Quantitative Test Results|date=August 2006|publisher=EUROLAB|location=Paris, France|page=8|url=http://www.eurolab.org/documents/EL_11_01_06_387%20Technical%20report%20-%20Guide%20Measurement%20uncertainty.pdf|access-date=2 March 2017|url-status=live|archive-url=https://web.archive.org/web/20161123053518/http://www.eurolab.org/documents/EL_11_01_06_387%20Technical%20report%20-%20Guide%20Measurement%20uncertainty.pdf|archive-date=23 November 2016}} There are two components to the uncertainty of a measurement: the width of the uncertainty interval and the confidence level.{{cite journal|last1=Bell|first1=Stephanie|title=A Beginner's Guide to Uncertainty of Measurement|journal=Technical Review- National Physical Laboratory|date=March 2001|publisher=National Physical Laboratory|location=Teddington, Middlesex, United Kingdom|issn=1368-6550|edition=Issue 2|url=https://www.wmo.int/pages/prog/gcos/documents/gruanmanuals/UK_NPL/mgpg11.pdf|access-date=2 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170503205533/https://www.wmo.int/pages/prog/gcos/documents/gruanmanuals/UK_NPL/mgpg11.pdf|archive-date=3 May 2017}} The uncertainty interval is a range of values that the measurement value expected to fall within, while the confidence level is how likely the true value is to fall within the uncertainty interval. Uncertainty is generally expressed as follows: [133] => :Y = y \pm U [134] => :Coverage factor: ''k'' = 2 [135] => Where ''y'' is the measurement value and ''U'' is the uncertainty value and ''k'' is the coverage factor{{efn|Equivalent to standard deviation if the uncertainty distribution is normal}} indicates the confidence interval. The upper and lower limit of the uncertainty interval can be determined by adding and subtracting the uncertainty value from the measurement value. The coverage factor of ''k'' = 2 generally indicates a 95% confidence that the measured value will fall inside the uncertainty interval. Other values of ''k'' can be used to indicate a greater or lower confidence on the interval, for example ''k'' = 1 and ''k'' = 3 generally indicate 66% and 99.7% confidence respectively. The uncertainty value is determined through a combination of statistical analysis of the calibration and uncertainty contribution from other errors in measurement process, which can be evaluated from sources such as the instrument history, manufacturer's specifications, or published information. [136] => == International infrastructure == [137] => Several international organizations maintain and standardise metrology. [138] => [139] => === Metre Convention === [140] => [141] => The [[Metre Convention]] created three main [[international organization]]s to facilitate standardisation of weights and measures. The first, the General Conference on Weights and Measures (CGPM), provided a forum for representatives of member states. The second, the International Committee for Weights and Measures (CIPM), was an advisory committee of metrologists of high standing. The third, the International Bureau of Weights and Measures (BIPM), provided secretarial and laboratory facilities for the CGPM and CIPM.{{cite web|url=http://www.bipm.org/en/convention/|title=The Metre Convention|publisher=Bureau International des Poids et Mesures|access-date=1 October 2012|url-status=live|archive-url=https://web.archive.org/web/20120926202046/http://www.bipm.org/en/convention/|archive-date=26 September 2012}} [142] => [143] => ====General Conference on Weights and Measures==== [144] => The [[General Conference on Weights and Measures]] ({{lang-fr|Conférence générale des poids et mesures}}, or CGPM) is the convention's principal decision-making body, consisting of delegates from member states and non-voting observers from associate states.{{cite web|url = http://www.bipm.org/en/convention/cgpm/|title = General Conference on Weights and Measures|year = 2011|publisher = Bureau International des Poids et Mesures|access-date = 26 September 2012|url-status = dead|archive-url = https://web.archive.org/web/20120926233323/http://www.bipm.org/en/convention/cgpm/|archive-date = 26 September 2012}} The conference usually meets every four to six years to receive and discuss a CIPM report and endorse new developments in the SI as advised by the CIPM. The last meeting was held on 13–16 November 2018. On the last day of this conference there was vote on the redefinition of four base units, which the [[International Committee for Weights and Measures]] (CIPM) had proposed earlier that year. [145] => {{cite conference [146] => |title=Proceedings of the 106th meeting [147] => |conference=International Committee for Weights and Measures [148] => |date=16–20 October 2017 [149] => |url=https://www.bipm.org/utils/en/pdf/CIPM/CIPM2017-EN.pdf?page=23 [150] => |conference-url=https://www.bipm.org/en/committees/cipm/meeting/106.html [151] => |location=Sèvres [152] => }} The new definitions came into force on 20 May 2019.{{citation [153] => |url=https://www.bipm.org/utils/common/pdf/SI-statement.pdf [154] => |title=BIPM statement: Information for users about the proposed revision of the SI [155] => |access-date=2018-11-22 [156] => |archive-date=2018-01-21 [157] => |archive-url=https://web.archive.org/web/20180121160000/https://www.bipm.org/utils/common/pdf/SI-statement.pdf [158] => |url-status=dead [159] => }}[http://www.bipm.org/en/committees/cipm/meeting/105.html "Decision CIPM/105-13 (October 2016)"]. The day is the 144th anniversary of the [[Metre Convention]]. [160] => [161] => ====International Committee for Weights and Measures==== [162] => [163] => The [[International Committee for Weights and Measures]] ({{lang-fr|Comité international des poids et mesures}}, or CIPM) is made up of eighteen (originally fourteen)Convention of the Metre (1875), Appendix 1 (Regulation), Article 8 individuals from a member state of high scientific standing, nominated by the CGPM to advise the CGPM on administrative and technical matters. It is responsible for ten consultative committees (CCs), each of which investigates a different aspect of metrology; one CC discusses the measurement of temperature, another the measurement of mass, and so forth. The CIPM meets annually in [[Sèvres]] to discuss reports from the CCs, to submit an annual report to the governments of member states concerning the administration and finances of the BIPM and to advise the CGPM on technical matters as needed. Each member of the CIPM is from a different member state, with France (in recognition of its role in establishing the convention) always having one seat.{{cite web|url = http://www.bipm.org/en/committees/cipm/|title = CIPM: International Committee for Weights and Measures|year = 2011|publisher = Bureau International des Poids et Mesures|access-date = 26 September 2012|url-status = live|archive-url = https://web.archive.org/web/20120924192125/http://www.bipm.org/en/committees/cipm/|archive-date = 24 September 2012}}{{cite web|url = http://www.bipm.org/en/committees/cipm/cipm_criteria.html|title = Criteria for membership of the CIPM|year = 2011|publisher = Bureau International des Poids et Mesures|access-date = 26 September 2012|url-status = dead|archive-url = https://web.archive.org/web/20120527174210/http://www.bipm.org/en/committees/cipm/cipm_criteria.html|archive-date = 27 May 2012}} [164] => [165] => ====International Bureau of Weights and Measures==== [166] => [[File:Metric seal.svg|thumb|upright|alt=BIPM seal: three women, one holding a measuring stick|BIPM seal]] [167] => The [[International Bureau of Weights and Measures]] ({{lang-fr|Bureau international des poids et mesures}}, or BIPM) is an organisation based in Sèvres, France which has custody of the [[international prototype of the kilogram]], provides metrology services for the CGPM and CIPM, houses the secretariat for the organisations and hosts their meetings.{{cite web|title=Mission, Role and Objectives|url=https://www.bipm.org/utils/en/pdf/BIPM-MissionRoleObjectives.pdf|publisher=BIPM|access-date=26 March 2018|archive-date=6 October 2016|archive-url=https://web.archive.org/web/20161006231136/http://www.bipm.org/utils/en/pdf/BIPM-MissionRoleObjectives.pdf|url-status=dead}}{{cite web|title=International Prototype of the Kilogram|url=https://www.bipm.org/en/bipm/mass/ipk/|publisher=BIPM|access-date=26 March 2018|archive-date=12 March 2020|archive-url=https://web.archive.org/web/20200312065104/https://www.bipm.org/en/bipm/mass/ipk/|url-status=dead}} Over the years, prototypes of the metre and of the kilogram have been returned to BIPM headquarters for recalibration. The BIPM director is an [[ex officio member]] of the CIPM and a member of all consultative committees.{{cite web|title=Criteria for membership of a Consultative Committee|url=https://www.bipm.org/en/committees/cc/cc-criteria.html|publisher=BIPM|access-date=26 March 2018|archive-date=26 March 2018|archive-url=https://web.archive.org/web/20180326202532/https://www.bipm.org/en/committees/cc/cc-criteria.html|url-status=dead}} [168] => [169] => === International Organization of Legal Metrology === [170] => [171] => The [[International Organization of Legal Metrology]] ({{lang-fr|Organisation Internationale de Métrologie Légale}}, or OIML), is an [[intergovernmental organization]] created in 1955 to promote the global harmonisation of the legal metrology procedures facilitating international trade.{{cite journal|title=Convention establishing an International Organisation of Legal Metrology|volume=2000 (E)|url=https://www.oiml.org/en/files/pdf_b/b001-e68.pdf|access-date=24 March 2017|publisher=Bureau International de Métrologie Légale|location=Paris|url-status=live|archive-url=https://web.archive.org/web/20140712233521/http://www.oiml.org/en/files/pdf_b/b001-e68.pdf|archive-date=12 July 2014}} This harmonisation of technical requirements, test procedures and test-report formats ensure confidence in measurements for trade and reduces the costs of discrepancies and measurement duplication.{{cite journal|url = https://www.oiml.org/en/files/pdf_b/b015-e11.pdf|title = OIML Strategy|volume = OIML B 15|edition = 2011 (E)|publisher = Bureau International de Métrologie Légale|location = Paris|access-date = 24 March 2017|url-status = live|archive-url = https://web.archive.org/web/20161202233613/https://www.oiml.org/en/files/pdf_b/b015-e11.pdf|archive-date = 2 December 2016}} The OIML publishes a number of international reports in four categories: [172] => *Recommendations: Model regulations to establish metrological characteristics and conformity of measuring instruments [173] => *Informative documents: To harmonise legal metrology [174] => *Guidelines for the application of legal metrology [175] => *Basic publications: Definitions of the operating rules of the OIML structure and system [176] => [177] => Although the OIML has no legal authority to impose its recommendations and guidelines on its member countries, it provides a standardised legal framework for those countries to assist the development of appropriate, harmonised legislation for certification and calibration. OIML provides a mutual acceptance arrangement (MAA) for measuring instruments that are subject to legal metrological control, which upon approval allows the evaluation and test reports of the instrument to be accepted in all participating countries.{{cite web|title=MAA certificates|url=https://www.oiml.org/en/certificates/maa-certificates|publisher=OIML|access-date=25 March 2018|language=en}} Issuing participants in the agreement issue MAA Type Evaluation Reports of MAA Certificates upon demonstration of compliance with ISO/IEC 17065 and a peer evaluation system to determine competency. This ensures that certification of measuring devices in one country is compatible with the certification process in other participating countries, allowing the trade of the measuring devices and the products that rely on them. [178] => [179] => === International Laboratory Accreditation Cooperation === [180] => The [[International Laboratory Accreditation Cooperation]] (ILAC) is an international organisation for accreditation agencies involved in the certification of conformity-assessment bodies.{{cite web|title=ABOUT ILAC|url=http://ilac.org/about-ilac/|publisher=International Laboratory Accreditation Cooperation|access-date=24 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170315033033/http://ilac.org/about-ilac/|archive-date=15 March 2017}} It standardises accreditation practices and procedures, recognising competent calibration facilities and assisting countries developing their own accreditation bodies. ILAC originally began as a conference in 1977 to develop international cooperation for accredited testing and calibration results to facilitate trade. In 2000, 36 members signed the ILAC [[mutual recognition agreement]] (MRA), allowing members work to be automatically accepted by other signatories, and in 2012 was expanded to include accreditation of inspection bodies.{{cite web|title=The ILAC Mutual Recognition Arrangement|url=https://www.a2la.org/ILAC/ILAC_MRA_English.pdf|publisher=International Laboratory Accreditation Cooperation|access-date=24 March 2017|url-status=dead|archive-url=https://web.archive.org/web/20170325201512/https://www.a2la.org/ILAC/ILAC_MRA_English.pdf|archive-date=25 March 2017}} Through this standardisation, work done in laboratories accredited by signatories is automatically recognised internationally through the MRA.{{cite web|title=ILAC's Role International Laboratory Accreditation Cooperation|url=http://ilac.org/about-ilac/role/|publisher=ILAC|access-date=25 March 2018|language=en}} Other work done by ILAC includes promotion of laboratory and inspection body accreditation, and supporting the development of accreditation systems in developing economies. [181] => [182] => === Joint Committee for Guides in Metrology === [183] => [184] => The [[Joint Committee for Guides in Metrology]] (JCGM) is a committee which created and maintains two metrology guides: ''Guide to the expression of uncertainty in measurement'' (GUM)[http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf JCGM 100:2008. Evaluation of measurement data – Guide to the expression of uncertainty in measurement, Joint Committee for Guides in Metrology.] {{webarchive|url=https://web.archive.org/web/20091001153550/http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf |date=2009-10-01 }} and ''International vocabulary of metrology – basic and general concepts and associated terms'' (VIM). The JCGM is a collaboration of eight partner organisations:{{cite book|title=Charter Joint Committee for Guides in Metrology (JCGM)|date=10 December 2009|publisher=Joint Committee for Guides in Metrology|url=http://www.bipm.org/utils/en/pdf/JCGM-charter.pdf|access-date=24 March 2017|url-status=live|archive-url=https://web.archive.org/web/20151024122615/http://www.bipm.org/utils/en/pdf/JCGM-charter.pdf|archive-date=24 October 2015}} [185] => * International Bureau of Weights and Measures (BIPM) [186] => * [[International Electrotechnical Commission]] (IEC) [187] => * [[International Federation of Clinical Chemistry and Laboratory Medicine]] (IFCC) [188] => * [[International Organization for Standardization]] (ISO) [189] => * [[International Union of Pure and Applied Chemistry]] (IUPAC) [190] => * [[International Union of Pure and Applied Physics]] (IUPAP) [191] => * International Organization of Legal Metrology (OIML) [192] => * International Laboratory Accreditation Cooperation (ILAC) [193] => [194] => The JCGM has two working groups: JCGM-WG1 and JCGM-WG2. JCGM-WG1 is responsible for the GUM, and JCGM-WG2 for the VIM.{{cite web|title=Joint Committee for Guides in Metrology (JCGM)|url=http://www.bipm.org/en/committees/jc/jcgm/|publisher=Bureau International des Poids et Mesures|access-date=24 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170512161807/http://www.bipm.org/en/committees/jc/jcgm/|archive-date=12 May 2017}} Each member organization appoints one representative and up to two experts to attend each meeting, and may appoint up to three experts for each working group. [195] => [196] => == National infrastructure == [197] => A national measurement system (NMS) is a network of laboratories, calibration facilities and accreditation bodies which implement and maintain a country's measurement infrastructure.{{cite web|title=The National Quality Infrastructure|url=https://innovationpolicyplatform.org/sites/default/files/rdf_imported_documents/TheNationalQualityInfrastructure.pdf|publisher=The Innovation Policy Platform|access-date=5 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170306130935/https://innovationpolicyplatform.org/sites/default/files/rdf_imported_documents/TheNationalQualityInfrastructure.pdf|archive-date=6 March 2017}} The NMS sets measurement standards, ensuring the accuracy, consistency, comparability, and reliability of measurements made in the country.{{cite web|title=National Measurement System|url=https://nmckh.wordpress.com/about/national-measurement-system/|publisher=National Metrology Center (NMC)|access-date=5 March 2017|date=23 August 2013|url-status=dead|archive-url=https://web.archive.org/web/20170306033754/https://nmckh.wordpress.com/about/national-measurement-system/|archive-date=6 March 2017}} The measurements of member countries of the CIPM Mutual Recognition Arrangement (CIPM MRA), an agreement of national metrology institutes, are recognized by other member countries. As of March 2018, there are 102 signatories of the CIPM MRA, consisting of 58 member states, 40 associate states, and 4 international organizations.{{cite web|title=BIPM – signatories|url=https://www.bipm.org/en/cipm-mra/participation/signatories.html|website=www.bipm.org|publisher=Bureau International des Poids et Mesures|access-date=24 March 2018}} [198] => [199] => === {{anchor|National metrology institutes}}Metrology institutes === [200] => [[File:National Measurement System Overview.png|thumb|alt=Block diagram|Overview of a national measurement system]] [201] => A national metrology institute's (NMI) role in a country's measurement system is to conduct scientific metrology, realise base units, and maintain primary national standards. An NMI provides traceability to international standards for a country, anchoring its national calibration hierarchy. For a national measurement system to be recognized internationally by the CIPM Mutual Recognition Arrangement, an NMI must participate in international comparisons of its measurement capabilities. BIPM maintains a comparison database and a list of calibration and measurement capabilities (CMCs) of the countries participating in the CIPM MRA.{{cite web|title=The BIPM key comparison database|url=http://kcdb.bipm.org/|publisher=Bureau International des Poids et Mesures|access-date=5 March 2017|url-status=dead|archive-url=https://web.archive.org/web/20170129024102/http://kcdb.bipm.org/|archive-date=29 January 2017}} Not all countries have a centralised metrology institute; some have a lead NMI and several decentralised institutes specialising in specific national standards. Some examples of NMI's are the [[National Institute of Standards and Technology]] (NIST){{cite journal|title=International Legal Organizational Primer|url=https://www.nist.gov/pml/weights-and-measures/international-legal-metrology/ilmp-organizational-primer|journal=NIST|access-date=25 March 2018|language=en|date=14 January 2010}} in the United States, the [[National Research Council (Canada)|National Research Council]] (NRC){{cite web|title=Measurement science and standards – National Research Council Canada|url=https://www.nrc-cnrc.gc.ca/eng/rd/mss/index.html|publisher=National Research Council of Canada|access-date=25 March 2018|language=en}} in Canada, the [[Physikalisch-Technische Bundesanstalt]] (PTB) in Germany,{{cite web|title=PTB|url=https://www.ptb.de/cms/en/|publisher=PTB|access-date=18 June 2023|language=en}} and the [[National Physical Laboratory (United Kingdom)]] (NPL).{{cite web|title=Creating impact from science and engineering – National Physical Laboratory|url=http://www.npl.co.uk|publisher=National Physical Laboratory|access-date=25 January 2022|language=en|date=17 June 2017}} [202] => [203] => === Calibration laboratories === [204] => Calibration laboratories are generally responsible for calibrations of industrial instrumentation. Calibration laboratories are accredited and provide calibration services to industry firms, which provides a traceability link back to the national metrology institute. Since the calibration laboratories are accredited, they give companies a traceability link to national metrology standards. [205] => [206] => === Accreditation bodies === [207] => An organisation is accredited when an authoritative body determines, by assessing the organisation's personnel and management systems, that it is competent to provide its services. For international recognition, a country's accreditation body must comply with international requirements and is generally the product of international and regional cooperation. A laboratory is evaluated according to international standards such as [[ISO/IEC 17025]] general requirements for the competence of testing and calibration laboratories. To ensure objective and technically-credible accreditation, the bodies are independent of other national measurement system institutions. The [[National Association of Testing Authorities]]{{cite web|title=NATA – About Us|url=http://www.nata.com.au/about-nata|publisher=NATA|access-date=25 March 2018|language=en-gb}} in Australia and the [[United Kingdom Accreditation Service]]{{cite web|title=About UKAS|url=https://www.ukas.com/about/|publisher=UKAS|access-date=25 March 2018|language=en}} are examples of accreditation bodies. [208] => [209] => == {{anchor|Societal impact}}Impacts == [210] => Metrology has wide-ranging impacts on a number of sectors, including economics, energy, the environment, health, manufacturing, industry, and consumer confidence.{{cite web|title=Metrology for Society's Challenges|url=https://www.euramet.org/metrology-for-societys-challenges/|publisher=EURAMET|access-date=9 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170312083228/https://www.euramet.org/metrology-for-societys-challenges/|archive-date=12 March 2017}}{{cite book|last1=Robertson|first1=Kristel|last2=Swanepoel|first2=Jan A.|title=The economics of metrology|date=September 2015|publisher=Australian Government, Department of Industry, Innovation and Science|url=https://industry.gov.au/Office-of-the-Chief-Economist/Research-Papers/Documents/2015-Research-Paper-6-The-economics-of-metrology.pdf|access-date=9 March 2017|url-status=live|archive-url=https://web.archive.org/web/20160307031140/http://www.industry.gov.au/Office-of-the-Chief-Economist/Research-Papers/Documents/2015-Research-Paper-6-The-economics-of-metrology.pdf|archive-date=7 March 2016}} The effects of metrology on trade and the economy are two of its most-apparent societal impacts. To facilitate fair and accurate trade between countries, there must be an agreed-upon system of measurement. Accurate measurement and regulation of water, fuel, food, and electricity are critical for [[consumer protection]] and promote the flow of goods and services between trading partners.{{cite journal|last1=Rodrigues Filho|first1=Bruno A.|last2=Gonçalves|first2=Rodrigo F.|title=Legal metrology, the economy and society: A systematic literature review|journal=Measurement|date=June 2015|volume=69|pages=155–163|doi=10.1016/j.measurement.2015.03.028|bibcode=2015Meas...69..155R}} A common measurement system and quality standards benefit consumer and producer; production at a common standard reduces cost and consumer risk, ensuring that the product meets consumer needs. Transaction costs are reduced through an increased [[Economies of scale|economy of scale]]. Several studies have indicated that increased standardisation in measurement has a positive impact on [[Gross domestic product|GDP]]. In the United Kingdom, an estimated 28.4 per cent of GDP growth from 1921 to 2013 was the result of standardisation; in Canada between 1981 and 2004 an estimated nine per cent of GDP growth was standardisation-related, and in Germany the annual economic benefit of standardisation is an estimated 0.72% of GDP. [211] => [212] => Legal metrology has reduced accidental deaths and injuries with measuring devices, such as [[radar gun]]s and [[breathalyzer]]s, by improving their efficiency and reliability. Measuring the human body is challenging, with poor [[repeatability]] and [[reproducibility]], and advances in metrology help develop new techniques to improve health care and reduce costs.{{cite web|title=Metrology for Society's Challenges – Metrology for Health|url=https://www.euramet.org/metrology-for-societys-challenges/metrology-for-health/|publisher=EURAMET|access-date=9 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170312083223/https://www.euramet.org/metrology-for-societys-challenges/metrology-for-health/|archive-date=12 March 2017}} Environmental policy is based on research data, and accurate measurements are important for assessing [[climate change]] and environmental regulation.{{cite web|title=Metrology for Society's Challenges – Metrology for Environment|url=https://www.euramet.org/metrology-for-societys-challenges/metrology-for-environment/|publisher=EURAMET|access-date=9 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170312083340/https://www.euramet.org/metrology-for-societys-challenges/metrology-for-environment/|archive-date=12 March 2017}} Aside from regulation, metrology is essential in supporting innovation, the ability to measure provides a technical infrastructure and tools that can then be used to pursue further innovation. By providing a technical platform which new ideas can be built upon, easily demonstrated, and shared, measurement standards allow new ideas to be explored and expanded upon. [213] => [214] => ==See also== [215] => {{Main|Outline of metrology and measurement}} [216] => {{cols|colwidth=24em}} [217] => * [[Accuracy and precision]] [218] => * [[Dimensional metrology]] [219] => * [[Forensic metrology]] [220] => * [[Geometric dimensioning and tolerancing]] [221] => * [[Historical metrology]] [222] => * [[International vocabulary of metrology]] [223] => * [[Length measurement]] [224] => * ''[[Measurement (journal)|Measurement]]'' ([[academic journal]]) [225] => * [[Metrication]] [226] => * ''[[Metrologia]]'' ([[academic journal]]) [227] => * [[Smart Metrology]] [228] => * [[Time metrology]] [229] => * [[World Metrology Day]] [230] => * [[Quantum metrology]] [231] => {{colend}} [232] => [233] => == Notes == [234] => {{Notelist}} [235] => [236] => == References == [237] => {{Reflist|30em}} [238] => [239] => ==External links== [240] => {{Commons category|Metrology}} [241] => * [https://link.springer.com/book/10.1007/b138915 Measurement Uncertainties in Science and Technology, Springer 2005] [242] => * [http://elsmar.com/APQP/ Presentation about Product Quality planning that includes a typical industry "Dimensional Control Plan" ] [243] => * [http://www.trainmic.org/ Training in Metrology in Chemistry (TrainMiC)] [244] => * [http://www.msc-euromaster.eu/ Measurement Science in Chemistry] [245] => {{Authority control}} [246] => [247] => [[Category:Metrology| ]] [] => )
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Metrology

Metrology is the scientific study of measurement. It encompasses a wide range of activities, including the development of measurement standards, calibration of measuring instruments, and the establishment of measurement techniques and procedures.

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It encompasses a wide range of activities, including the development of measurement standards, calibration of measuring instruments, and the establishment of measurement techniques and procedures. The field of metrology plays a critical role in ensuring the accuracy and reliability of measurements across various industries and sectors, such as manufacturing, healthcare, and environmental monitoring. Metrologists work with a variety of measurement instruments, such as rulers, scales, oscilloscopes, and spectrophotometers, to quantify physical properties and ensure consistency and uniformity in measurements. This Wikipedia page on metrology provides a comprehensive overview of the field, including its history, principles, applications, and various measurement techniques and instruments used.

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Reproducibility, closely related to replicability and repeatability, is a major principle underpinning the scientific method.

Time

Time is a concept that represents the ongoing sequence of events occurring in an irreversible succession, from the past through the present to the future.

Vacuum

A vacuum is a space devoid of matter, such as air or other gases.