In mathematics and empirical science , quantification (or quantitation ) is the act of counting and measuring that maps human sense observations and experiences into quantities . Quantification in this sense is fundamental to the scientific method .
61-499: Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering , measurements do not apply to nominal properties of objects or events, which
122-481: A comparison framework. The system defines seven fundamental units : kilogram , metre , candela , second , ampere , kelvin , and mole . All of these units are defined without reference to a particular physical object which serves as a standard. Artifact-free definitions fix measurements at an exact value related to a physical constant or other invariable phenomena in nature, in contrast to standard artifacts which are subject to deterioration or destruction. Instead,
183-615: A different nationality. elected by the General Conference on Weights and Measures (CGPM) whose principal task is to promote worldwide uniformity in units of measurement by taking direct action or by submitting proposals to the CGPM. The CIPM meets every year (since 2011 in two sessions per year) at the Pavillon de Breteuil where, among other matters, it discusses reports presented to it by its Consultative Committees. Reports of
244-458: A digital read-out, but require a gravitational field to function and would not work in free fall. The measures used in economics are physical measures, nominal price value measures and real price measures. These measures differ from one another by the variables they measure and by the variables excluded from measurements. In the field of survey research, measures are taken from individual attitudes, values, and behavior using questionnaires as
305-522: A distance of one metre (about 39 in ). Using physics, it can be shown that, in the gravitational field of the Earth, it should take any object about 0.45 second to fall one metre. However, the following are just some of the sources of error that arise: Additionally, other sources of experimental error include: Scientific experiments must be carried out with great care to eliminate as much error as possible, and to keep error estimates realistic. In
366-460: A few examples. Imperial units are used in many other places, for example, in many Commonwealth countries that are considered metricated, land area is measured in acres and floor space in square feet, particularly for commercial transactions (rather than government statistics). Similarly, gasoline is sold by the gallon in many countries that are considered metricated. The metric system is a decimal system of measurement based on its units for length,
427-438: A filter, changing the quantum state into one with the single measured quantum value. The unambiguous meaning of the quantum measurement is an unresolved fundamental problem in quantum mechanics ; the most common interpretation is that when a measurement is performed, the wavefunction of the quantum system " collapses " to a single, definite value. In biology, there is generally no well established theory of measurement. However,
488-419: A measurement instrument. As all other measurements, measurement in survey research is also vulnerable to measurement error , i.e. the departure from the true value of the measurement and the value provided using the measurement instrument. In substantive survey research, measurement error can lead to biased conclusions and wrongly estimated effects. In order to get accurate results, when measurement errors appear,
549-407: A measurement is an action that determines a particular property (position, momentum, energy, etc.) of a quantum system. Quantum measurements are always statistical samples from a probability distribution; the distribution for many quantum phenomena is discrete. Quantum measurements alter quantum states and yet repeated measurements on a quantum state are reproducible. The measurement appears to act as
610-514: A member of the CIPM. Apart from the CCU, membership of a CC is open to National Metrology Institutes ( NMIs ) of Member States that are recognized internationally as most expert in the field. NMIs from Member States that are active in the field, but lack the expertise to become Members, are able to attend CC meetings as observers. These committees are: The CCU's role is to advise on matters related to
671-634: A scientific basis, overseen by governmental or independent agencies, and established in international treaties, pre-eminent of which is the General Conference on Weights and Measures (CGPM), established in 1875 by the Metre Convention , overseeing the International System of Units (SI). For example, the metre was redefined in 1983 by the CGPM in terms of the speed of light, the kilogram was redefined in 2019 in terms of
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#1732764876783732-437: A seemingly intangible property may be quantified by asking subjects to rate something on a scale —for example, a happiness scale or a quality-of-life scale —or by the construction of a scale by the researcher, as with the index of economic freedom . In other cases, an unobservable variable may be quantified by replacing it with a proxy variable with which it is highly correlated—for example, per capita gross domestic product
793-510: Is an apparently irreversible series of occurrences within this non spatial continuum. It is also used to denote an interval between two relative points on this continuum. Mass refers to the intrinsic property of all material objects to resist changes in their momentum. Weight , on the other hand, refers to the downward force produced when a mass is in a gravitational field. In free fall , (no net gravitational forces) objects lack weight but retain their mass. The Imperial units of mass include
854-651: Is consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures . However, in other fields such as statistics as well as the social and behavioural sciences , measurements can have multiple levels , which would include nominal, ordinal, interval and ratio scales. Measurement is a cornerstone of trade , science , technology and quantitative research in many disciplines. Historically, many measurement systems existed for
915-520: Is often used as a proxy for standard of living or quality of life . Frequently in the use of regression, the presence or absence of a trait is quantified by employing a dummy variable , which takes on the value 1 in the presence of the trait or the value 0 in the absence of the trait. Quantitative linguistics is an area of linguistics that relies on quantification. For example, indices of grammaticalization of morphemes , such as phonological shortness, dependence on surroundings, and fusion with
976-483: Is pursued in the field of metrology . Measurement is defined as the process of comparison of an unknown quantity with a known or standard quantity. The measurement of a property may be categorized by the following criteria: type , magnitude , unit , and uncertainty . They enable unambiguous comparisons between measurements. Measurements most commonly use the International System of Units (SI) as
1037-401: Is quantitative if such structural similarities can be established. In weaker forms of representational theory, such as that implicit within the work of Stanley Smith Stevens , numbers need only be assigned according to a rule. The concept of measurement is often misunderstood as merely the assignment of a value, but it is possible to assign a value in a way that is not a measurement in terms of
1098-601: The Commonwealth and the United States. The system came to be known as U.S. customary units in the United States and is still in use there and in a few Caribbean countries. These various systems of measurement have at times been called foot-pound-second systems after the Imperial units for length, weight and time even though the tons, hundredweights, gallons, and nautical miles, for example, are different for
1159-590: The Convention du Mètre ( Metre Convention ) was signed by 17 states. This treaty established an international organisation, the Bureau international des poids et mesures (BIPM), which has two governing organs: The organization has a permanent laboratory and secretariat function (sometimes referred to as the Headquarters), the activities of which include the establishment of the basic standards and scales of
1220-468: The French : Conférence générale des poids et mesures ) is the supreme authority of the International Bureau of Weights and Measures (BIPM), the intergovernmental organization established in 1875 under the terms of the Metre Convention through which member states act together on matters related to measurement science and measurement standards . The CGPM is made up of delegates of the governments of
1281-435: The French language name Système International d'Unités ) is the modern revision of the metric system . It is the world's most widely used system of units , both in everyday commerce and in science . The SI was developed in 1960 from the metre–kilogram–second (MKS) system, rather than the centimetre–gram–second (CGS) system, which, in turn, had many variants. The SI units for the seven base physical quantities are: In
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#17327648767831342-451: The International system of units . The brochure is produced by the CCU in conjunction with a number of other international organisations. Initially the brochure was only in French – the official language of the metre convention, but recent versions have been published simultaneously in both English and French, with the French text being the official text. The 6th edition was published in 1991,
1403-966: The National Physical Laboratory (NPL), in Australia by the National Measurement Institute , in South Africa by the Council for Scientific and Industrial Research and in India the National Physical Laboratory of India . unit is known or standard quantity in terms of which other physical quantities are measured. Before SI units were widely adopted around the world, the British systems of English units and later imperial units were used in Britain,
1464-673: The Planck constant and the international yard was defined in 1960 by the governments of the United States, United Kingdom, Australia and South Africa as being exactly 0.9144 metres. In the United States, the National Institute of Standards and Technology ( NIST ), a division of the United States Department of Commerce , regulates commercial measurements. In the United Kingdom, the role is performed by
1525-507: The metric system . In 1960 the 11th CGPM approved the title International System of Units , usually known as "SI". The General Conference receives the report of the CIPM on work accomplished; it discusses and examines the arrangements required to ensure the propagation and improvement of the International System of Units (SI); it endorses the results of new fundamental metrological determinations and various scientific resolutions of international scope; and it decides all major issues concerning
1586-420: The natural sciences can be gleaned from the following comments: This meaning of quantification comes under the heading of pragmatics . In some instances in the natural sciences a seemingly intangible concept may be quantified by creating a scale—for example, a pain scale in medical research, or a discomfort scale at the intersection of meteorology and human physiology such as the heat index measuring
1647-403: The ounce , pound , and ton . The metric units gram and kilogram are units of mass. One device for measuring weight or mass is called a weighing scale or, often, simply a scale . A spring scale measures force but not mass, a balance compares weight, both require a gravitational field to operate. Some of the most accurate instruments for measuring weight or mass are based on load cells with
1708-479: The ruler is the instrument used to rule straight lines and the calibrated instrument used for determining length is called a measure , however common usage calls both instruments rulers and the special name straightedge is used for an unmarked rule. The use of the word measure , in the sense of a measuring instrument, only survives in the phrase tape measure , an instrument that can be used to measure but cannot be used to draw straight lines. As can be seen in
1769-1115: The 21st meeting of the CGPM in October 1999, the category of "associate" was created for states not yet BIPM members and for economic unions . Albania (2007) Azerbaijan (2015) Bangladesh (2010) Bolivia (2008) Bosnia and Herzegovina (2011) Botswana (2012) Cambodia (2021) Caribbean Community (2005) Chinese Taipei (2002) Ethiopia (2018) Georgia (2008) Ghana (2009) Hong Kong (2000) Jamaica (2003) Kuwait (2018) Latvia (2001) Luxembourg (2014) Malta (2001) Mauritius (2010) Moldova (2007) Mongolia (2013) Namibia (2012) North Macedonia (2006) Oman (2012) Panama (2003) Paraguay (2009) Peru (2009) Philippines (2002) Qatar (2016) Sri Lanka (2007) Syria (2012) Tanzania (2018) Uzbekistan (2018) Vietnam (2003) Zambia (2010) Zimbabwe (2010–2020, 2022) Cuba (2000–2021) Seychelles (2010–2021) Sudan (2014–2021) The International Committee for Weights and Measures consists of eighteen persons, each of
1830-1808: The British Government signed the convention on behalf of the United Kingdom. This number grew to 21 in 1900, 32 in 1950, and 49 in 2001. As of 18 November 2022 , there are 64 Member States and 36 Associate States and Economies of the General Conference (with year of partnership in parentheses): Argentina (1877) Australia (1947) Austria (1875) Belarus (2020) Belgium (1875) Brazil (1921) Bulgaria (1911) Canada (1907) Chile (1908) China (1977) Colombia (2012) Costa Rica (2022) Croatia (2008) Czech Republic (1922) Denmark (1875) Ecuador (2019) Egypt (1962) Estonia (2021) Finland (1913) France (1875) Germany (1875) Greece (2001) Hungary (1925) India (1880) Indonesia (1960) Iran (1975) Iraq (2013) Ireland (1925) Israel (1985) Italy (1875) Japan (1885) Kazakhstan (2008) Kenya (2010) Lithuania (2015) Malaysia (2001) Mexico (1890) Montenegro (2018) Morocco (2019) Netherlands (1929) New Zealand (1991) Norway (1875) Pakistan (1973) Poland (1925) Portugal (1876) Romania (1884) Russia (1875) Saudi Arabia (2011) Serbia (2001) Singapore (1994) Slovakia (1922) Slovenia (2016) South Africa (1964) South Korea (1959) Spain (1875) Sweden (1875) Switzerland (1875) Thailand (1912) Tunisia (2012) Turkey (1875) Ukraine (2018) United Arab Emirates (2015) United Kingdom (1884) United States (1878) Uruguay (1908) Cameroon (1970–2012) Dominican Republic (1954–2015) North Korea (1982–2012) Peru (1875–1956) Venezuela (1879–1907, 1960–2018) At
1891-514: The CIPM include: From time to time the CIPM has been charged by the CGPM to undertake major investigations related to activities affecting the CGPM or the BIPM. Reports produced include: The Blevin Report , published in 1998, examined the state of worldwide metrology. The report originated from a resolution passed at the 20th CGPM (October 1995) which committed the CIPM to study and report on
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1952-616: The Conference of the Metre in 1875, representatives of seventeen signed the convention on 20 May 1875. In April 1884, H. J. Chaney, Warden of Standards in London unofficially contacted the BIPM inquiring whether the BIPM would calibrate some metre standards that had been manufactured in the United Kingdom. Broch , director of the BIPM replied that he was not authorised to perform any such calibrations for non-member states. On 17 September 1884,
2013-402: The International System of Units (SI), approves the budget for the BIPM (over €13 million in 2018) and it decides all major issues concerning the organization and development of the BIPM. The structure is analogous to that of a stock corporation . The BIPM is the organisation, the CGPM is the general meeting of the shareholders, the CIPM is the board of directors appointed by the CGPM, and
2074-509: The SI, base units are the simple measurements for time, length, mass, temperature, amount of substance, electric current and light intensity. Derived units are constructed from the base units, for example, the watt , i.e. the unit for power, is defined from the base units as m·kg·s. Other physical properties may be measured in compound units, such as material density, measured in kg/m. The SI allows easy multiplication when switching among units having
2135-405: The U.S. units. Many Imperial units remain in use in Britain, which has officially switched to the SI system—with a few exceptions such as road signs, which are still in miles. Draught beer and cider must be sold by the imperial pint, and milk in returnable bottles can be sold by the imperial pint. Many people measure their height in feet and inches and their weight in stone and pounds, to give just
2196-468: The classical definition, which is standard throughout the physical sciences, measurement is the determination or estimation of ratios of quantities. Quantity and measurement are mutually defined: quantitative attributes are those possible to measure, at least in principle. The classical concept of quantity can be traced back to John Wallis and Isaac Newton , and was foreshadowed in Euclid's Elements . In
2257-458: The combined perceived effect of heat and humidity , or the wind chill factor measuring the combined perceived effects of cold and wind. In the social sciences , quantification is an integral part of economics and psychology . Both disciplines gather data – economics by empirical observation and psychology by experimentation – and both use statistical techniques such as regression analysis to draw conclusions from it. In some instances
2318-475: The convention organisations and national governments is handled by the member state's ambassador to France, it is implicit that member states must have diplomatic relations with France, though during both world wars, nations that were at war with France retained their membership of the CGPM. CGPM meetings are chaired by the Président de l'Académie des Sciences de Paris . Of the twenty countries that attended
2379-416: The development of the SI and the preparation of the SI brochure. It has liaison with other international bodies such as International Organization for Standardization (ISO) , International Astronomical Union (IAU) , International Union of Pure and Applied Chemistry (IUPAC) , International Union of Pure and Applied Physics (IUPAP) and International Commission on Illumination (CIE) . Official reports of
2440-579: The exception of a few fundamental quantum constants, units of measurement are derived from historical agreements. Nothing inherent in nature dictates that an inch has to be a certain length, nor that a mile is a better measure of distance than a kilometre . Over the course of human history, however, first for convenience and then for necessity, standards of measurement evolved so that communities would have certain common benchmarks. Laws regulating measurement were originally developed to prevent fraud in commerce. Units of measurement are generally defined on
2501-428: The expected value of a quantity, and then, using various methods and instruments, reduces the uncertainty in the value. In this view, unlike the positivist representational theory, all measurements are uncertain, so instead of assigning one value, a range of values is assigned to a measurement. This also implies that there is not a clear or neat distinction between estimation and measurement. In quantum mechanics ,
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2562-445: The importance of the theoretical context is emphasized. Moreover, the theoretical context stemming from the theory of evolution leads to articulate the theory of measurement and historicity as a fundamental notion. Among the most developed fields of measurement in biology are the measurement of genetic diversity and species diversity. Quantification (science) Some measure of the undisputed general importance of quantification in
2623-637: The long-term national and international needs relating to metrology, the appropriate international collaborations and the unique role of the BIPM to meet these needs, and the financial and other commitments that will be required from the Member States in the coming decades. The report identified, amongst other things, a need for closer cooperation between the BIPM and other organisations such as International Organization of Legal Metrology (OIML) and International Laboratory Accreditation Cooperation (ILAC) with clearly defined boundaries and interfaces between
2684-531: The measurement unit can only ever change through increased accuracy in determining the value of the constant it is tied to. The first proposal to tie an SI base unit to an experimental standard independent of fiat was by Charles Sanders Peirce (1839–1914), who proposed to define the metre in terms of the wavelength of a spectral line . This directly influenced the Michelson–Morley experiment ; Michelson and Morley cite Peirce, and improve on his method. With
2745-614: The meetings of the CGPM, the CIPM, and all the Consultative Committees, are published by the BIPM. The secretariat is based in Saint-Cloud , Hauts-de-Seine , France . In 1999, the CIPM has established the CIPM Arrangement de reconnaissance mutuelle (Mutual Recognition Arrangement, MRA), which serves as the framework for the mutual acceptance of national measurement standards and for recognition of
2806-726: The member states and observers from the Associates of the CGPM. It elects the International Committee for Weights and Measures (abbreviated CIPM from the Comité international des poids et mesures ) as the supervisory board of the BIPM to direct and supervise it. Initially the work of the BIPM concerned the kilogram and the metre , but in 1921 the scope of the Metre Convention was extended to accommodate all physical measurements and hence all aspects of
2867-446: The metre and for mass, the kilogram. It exists in several variations, with different choices of base units , though these do not affect its day-to-day use. Since the 1960s, the International System of Units (SI) is the internationally recognised metric system. Metric units of mass, length, and electricity are widely used around the world for both everyday and scientific purposes. The International System of Units (abbreviated as SI from
2928-458: The necessary criteria. Three type of representational theory All data are inexact and statistical in nature. Thus the definition of measurement is: "A set of observations that reduce uncertainty where the result is expressed as a quantity." This definition is implied in what scientists actually do when they measure something and report both the mean and statistics of the measurements. In practical terms, one begins with an initial guess as to
2989-415: The organisations. Another major finding was the need for cooperation between accreditation laboratories and the need to involve developing countries in the world of metrology. The Kaarls Report published in 2003 examined the role of the BIPM in the evolving needs for metrology in trade, industry and society. The CIPM has responsibility for commissioning the SI brochure, which is the formal definition of
3050-531: The organization and development of the BIPM, including its financial endowment. The CGPM meets in Paris, usually once every four years. The 25th meeting of the CGPM took place from 18 to 20 November 2014, the 26th meeting of the CGPM took place in Versailles from 13 to 16 November 2018, and the 27th meeting of the CGPM took place from 15 to 18 November 2022. On 20 May 1875 an international treaty known as
3111-415: The photographs on this page, a two-metre carpenter's rule can be folded down to a length of only 20 centimetres, to easily fit in a pocket, and a five-metre-long tape measure easily retracts to fit within a small housing. Time is an abstract measurement of elemental changes over a non-spatial continuum. It is denoted by numbers and/or named periods such as hours , days , weeks , months and years . It
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#17327648767833172-399: The principal physical quantities and maintenance of the international prototype standards. The CGPM acts on behalf of the governments of its members. In so doing, it elects members to the CIPM, receives reports from the CIPM which it passes on to the governments and national laboratories on member states, examines and where appropriate approves proposals from the CIPM in respect of changes to
3233-479: The qualitative evaluation of the broader contexts of qualitative data. In some social sciences such as sociology , quantitative data are difficult to obtain, either because laboratory conditions are not present or because the issues involved are conceptual but not directly quantifiable. Thus in these cases qualitative methods are preferred. General Conference on Weights and Measures The General Conference on Weights and Measures (abbreviated CGPM from
3294-431: The representational theory, measurement is defined as "the correlation of numbers with entities that are not numbers". The most technically elaborated form of representational theory is also known as additive conjoint measurement . In this form of representational theory, numbers are assigned based on correspondences or similarities between the structure of number systems and the structure of qualitative systems. A property
3355-438: The requirements of additive conjoint measurement. One may assign a value to a person's height, but unless it can be established that there is a correlation between measurements of height and empirical relations, it is not a measurement according to additive conjoint measurement theory. Likewise, computing and assigning arbitrary values, like the "book value" of an asset in accounting, is not a measurement because it does not satisfy
3416-427: The results need to be corrected for measurement errors . The following rules generally apply for displaying the exactness of measurements: Since accurate measurement is essential in many fields, and since all measurements are necessarily approximations, a great deal of effort must be taken to make measurements as accurate as possible. For example, consider the problem of measuring the time it takes an object to fall
3477-515: The same base but different prefixes. To convert from metres to centimetres it is only necessary to multiply the number of metres by 100, since there are 100 centimetres in a metre. Inversely, to switch from centimetres to metres one multiplies the number of centimetres by 0.01 or divides the number of centimetres by 100. A ruler or rule is a tool used in, for example, geometry , technical drawing , engineering, and carpentry, to measure lengths or distances or to draw straight lines. Strictly speaking,
3538-521: The staff at the site in Saint-Cloud perform the day-to-day work. The CGPM recognises two classes of membership – full membership for those states that wish to participate in the activities of the BIPM and associate membership for those countries or economies that only wish to participate in the CIPM MRA program. Associate members have observer status at the CGPM. Since all formal liaison between
3599-452: The validity of calibration and measurement certificates issued by national metrology institutes. A recent focus area of the CIPM has been the revision of the SI . The CIPM has set up a number of consultative committees (CC) to assist it in its work. These committees are under the authority of the CIPM. The president of each committee, who is expected to take the chair at CC meetings, is usually
3660-450: The varied fields of human existence to facilitate comparisons in these fields. Often these were achieved by local agreements between trading partners or collaborators. Since the 18th century, developments progressed towards unifying, widely accepted standards that resulted in the modern International System of Units (SI). This system reduces all physical measurements to a mathematical combination of seven base units. The science of measurement
3721-416: The verb, have been developed and found to be significantly correlated across languages with stage of evolution of function of the morpheme. The ease of quantification is one of the features used to distinguish hard and soft sciences from each other. Scientists often consider hard sciences to be more scientific or rigorous, but this is disputed by social scientists who maintain that appropriate rigor includes
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