Data (pron.: // DAY-tə, // DA-tə, or // DAH-tə) are values of qualitative or quantitative variables, belonging to a set of items. Data in computing (or data processing) are represented in a structure, often tabular (represented by rows and columns), a tree (a set of nodes with parent-children relationship) or a graph structure (a set of interconnected nodes). Data are typically the results of measurements and can be visualised using graphs or images. Data as an abstract concept can be viewed as the lowest level of abstraction from which information and then knowledge are derived. Raw data, i.e., unprocessed data, refers to a collection of numbers, characters and is a relative term; data processing commonly occurs by stages, and the "processed data" from one stage may be considered the "raw data" of the next. Field data refers to raw data collected in an uncontrolled in situ environment. Experimental data refers to data generated within the context of a scientific investigation by observation and recording.
The word data is the plural of datum, neuter past participle of the Latin dare, "to give", hence "something given". In discussions of problems in geometry, mathematics, engineering, and so on, the terms givens and data are used interchangeably. Such usage is the origin of data as a concept in computer science or data processing: data are numbers, words, images, etc., accepted as they stand.
Though data is also increasingly used in humanities (particularly in the growing digital humanities), it has been suggested that the highly interpretive nature of humanities might be at odds with the ethos of data as "given". Peter Checkland introduced the term capta (from the Latin capere, “to take”) to distinguish between an immense number of possible data and a sub-set of them, to which attention is oriented. Johanna Drucker has argued that since the humanities affirm knowledge production as “situated, partial, and constitutive,” using data may introduce assumptions that are counterproductive, for example that phenomena are discreet or are observer-independent. The term capta, which emphasizes the act of observation as constitutive, is offered as an alternative to data for visual representations in the humanities.
Usage in English 
In English, the word datum is still used in the general sense of "an item given". In cartography, geography, nuclear magnetic resonance and technical drawing it is often used to refer to a single specific reference datum from which distances to all other data are measured. Any measurement or result is a datum, but data point is more usual, albeit tautological or, more generously, pleonastic. In one sense, datum is a count noun with the plural datums (see usage in datum article) that can be used with cardinal numbers (e.g. "80 datums"); data (originally a Latin plural) is not used like a normal count noun with cardinal numbers, but it can be used as a plural with plural determiners such as these and many, in addition to its use as a singular abstract mass noun with a verb in the singular form. Even when a very small quantity of data is referenced (one number, for example) the phrase piece of data is often used, as opposed to datum. The debate over appropriate usage is ongoing.
The IEEE Computer Society allows usage of data as either a mass noun or plural based on author preference. Some professional organizations and style guides[dead link] require that authors treat data as a plural noun. For example, the Air Force Flight Test Center specifically states that the word data is always plural, never singular.
Data is most often used as a singular mass noun in educated everyday usage. Some major newspapers such as The New York Times use it either in the singular or plural. In the New York Times the phrases "the survey data are still being analyzed" and "the first year for which data is available" have appeared within one day. The Wall Street Journal explicitly allows this in its style guide. The Associated Press style guide classifies data as a collective noun that takes the singular when treated as a unit but the plural when referring to individual items ("The data is sound.", but "The data have been carefully collected.").
In scientific writing data is often treated as a plural, as in These data do not support the conclusions, but it is also used as a singular mass entity like information, for instance in computing and related disciplines. British usage now widely accepts treating data as singular in standard English, including everyday newspaper usage at least in non-scientific use. UK scientific publishing still prefers treating it as a plural. Some UK university style guides recommend using data for both singular and plural use and some recommend treating it only as a singular in connection with computers.
Meaning of data, information and knowledge 
The terms data, information and knowledge are frequently used for overlapping concepts. The main difference is in the level of abstraction being considered. Data is the lowest level of abstraction, information is the next level, and finally, knowledge is the highest level among all three. Data on its own carries no meaning. For data to become information, it must be interpreted and take on a meaning. For example, the height of Mt. Everest is generally considered as "data", a book on Mt. Everest geological characteristics may be considered as "information", and a report containing practical information on the best way to reach Mt. Everest's peak may be considered as "knowledge".
Information as a concept bears a diversity of meanings, from everyday usage to technical settings. Generally speaking, the concept of information is closely related to notions of constraint, communication, control, data, form, instruction, knowledge, meaning, mental stimulus, pattern, perception, and representation.
It is people and computers who collect data and impose patterns on it. These patterns are seen as information which can be used to enhance knowledge. These patterns can be interpreted as truth, and are authorized as aesthetic and ethical criteria. Events that leave behind perceivable physical or virtual remains can be traced back through data. Marks are no longer considered data once the link between the mark and observation is broken.
Mechanical computing devices are classified according to the means by which they represent data. An analog computer represents a datum as a voltage, distance, position, or other physical quantity. A digital computer represents a datum as a sequence of symbols drawn from a fixed alphabet. The most common digital computers use a binary alphabet, that is, an alphabet of two characters, typically denoted "0" and "1". More familiar representations, such as numbers or letters, are then constructed from the binary alphabet.
Some special forms of data are distinguished. A computer program is a collection of data, which can be interpreted as instructions. Most computer languages make a distinction between programs and the other data on which programs operate, but in some languages, notably Lisp and similar languages, programs are essentially indistinguishable from other data. It is also useful to distinguish metadata, that is, a description of other data. A similar yet earlier term for metadata is "ancillary data." The prototypical example of metadata is the library catalog, which is a description of the contents of books.
See also 
- Biological data
- Data acquisition
- Data analysis
- Data cable
- Data domain
- Data element
- Data farming
- Data governance
- Data integrity
- Data maintenance
- Data management
- Data mining
- Data modeling
- Computer data processing
- Data remanence
- Data set
- Data warehouse
- Environmental data rescue
- Scientific data archiving
- P. Checkland and S. Holwell (1998). Information, Systems, and Information Systems: Making Sense of the Field. Chichester, West Sussex: John Wiley & Sons. p. 86-89. ISBN 0-471-95820-4.
- Johanna Drucker (2011). "Humanities Approaches to Graphical Display".
- Matt Dye (2001). "Writing Reports". University of Bristol.
- "data, datum". Merriam–Webster's Dictionary of English Usage. Springfield, Massachusetts: Merriam-Webster. 2002. pp. 317–318. ISBN 978-0-87779-132-4.
- "Data is a singular noun".
- "Grammarist: Data".
- "Dictionary.com Data".
- "IEEE Computer Society Style Guide, DEF". IEEE Computer Society.
- "WHO Style Guide". Geneva: World Health Organization. 2004. p. 43.
- The Author's Guide to Writing Air Force Flight Test Center Technical Reports. Air Force Flight Test Center.
- New Oxford Dictionary of English, 1999
- "...in educated everyday usage as represented by the Guardian newspaper, it is nowadays most often used as a singular." http://www.lexically.net/TimJohns/Kibbitzer/revis006.htm
- "When Serving the Lord, Ministers Are Often Found to Neglect Themselves". New York Times. 2009."Investment Tax Cuts Help Mostly the Rich". New York Times. 2009.
- "Is Data Is, or Is Data Ain’t, a Plural?". Wall Street Journal. 2012.
- The Associated Press (June 2002). "collective nouns". In Norm Goldstein. The Associated Press Stylebook and Briefing on Media Law. Cambridge, Massachusetts: Perseus. p. 52. ISBN 0-7382-0740-3.
- R.W. Burchfield, ed. (1996). "data". Fowler's Modern English Usage (3rd ed.). Oxford: Clarendon Press. pp. 197–198. ISBN 0-19-869126-2.
- New Oxford Dictionary of English. 1999.
- Tim Johns (1997). "Data: singular or plural?". "...in educated everyday usage as represented by The Guardian newspaper, it is nowadays most often used as a singular."
- "Data". Compact Oxford Dictionary.
- "Data: singular or plural?". Blair Wisconsin International University.
- "Singular or plural". University of Nottingham Style Book. University of Nottingham.[dead link]
- "Computers and computer systems". OpenLearn.[dead link]
- Akash Mitra (2011). "Classifying data for successful modeling".
- P. Beynon-Davies (2002). Information Systems: An introduction to informatics in organisations. Basingstoke, UK: Palgrave Macmillan. ISBN 0-333-96390-3.
- P. Beynon-Davies (2009). Business information systems. Basingstoke, UK: Palgrave. ISBN 978-0-230-20368-6.
- Sharon Daniel. The Database: An Aesthetics of Dignity.
|Look up data in Wiktionary, the free dictionary.|
- Data is a singular noun (a detailed assessment)