Pie chart of populations of English native speakers

A pie chart (or a circle graph) is a circular chart divided into sectors, illustrating relative magnitudes or frequencies or percents. In a pie chart, the arc length of each sector (and consequently its central angle and area), is proportional to the quantity it represents. Together, the sectors create a full disk. It is named for its resemblance to a pie which has been sliced. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... The English language is a West Germanic language that originates in England. ... This article is about the shape and mathematical concept of circle. ... This article does not cite any references or sources. ... A circular sector or circle sector also known as a pie piece is the portion of a circle enclosed by two radii and an arc. ... The magnitude of a mathematical object is its size: a property by which it can be larger or smaller than other objects of the same kind; in technical terms, an ordering of the class of objects to which it belongs. ... Determining the length of an irregular arc segment—also called rectification of a curve—was historically difficult. ... Angle AOB forms a central angle of circle O A central angle is an angle whose vertex is the center of a circle, and whose sides pass through a pair of points on the circle, thereby subtending an arc between those two points whose angle is (by definition) equal to... This article is about the physical quantity. ... This article is about proportionality, the mathematical relation. ... This article is about the baked good, for other uses see Pie (disambiguation). ...

While the pie chart is perhaps the most ubiquitous statistical chart in the business world and the mass media, it is rarely used in scientific or technical publications.^[1] It is one of the most widely criticised charts,^[2] and many statisticians recommend to avoid its use altogether^[3][4], pointing out in particular that it is difficult to compare different sections of a given pie chart, or to compare data across different pie charts. Pie charts can be an effective way of displaying information in some cases, in particular if the intent is to compare the size of a slice with the whole pie, rather than comparing the slices among them.^[5] Pie charts work particularly well when the slices represent 25 or 50% of the data,^[6] but in general, other plots such as the bar chart or the dot plot, or non-graphical methods such as tables, may be more adapted for representing information. A bar chart is a chart with rectangular bars of lengths usually proportional to the magnitudes or frequencies of what they represent. ... A dot plot of 50 random values from 0 to 9. ... A table is a mode of visual communication that maps the logical structure of a set of data into a hierarchical matrix. ...

The earliest known pie chart is generally credited to William Playfair's Statistical Breviary of 1801.^[7][5] William Playfair (September 22, 1759 - February 11, 1823) a Scottish engineer and political economist, was an important inventor of statistical graphics. ... The Union Jack, flag of the newly formed United Kingdom of Great Britain and Ireland. ...

Example

A pie chart for the example data.

An exploded pie chart for the example data, with the largest party group exploded.

The following example chart is based on preliminary results of the election for the European Parliament in 2004. The following table lists the number of seats allocated to each party group, along with the derived percentage of the total that they each make up. The values in the last column, the derived central angle of each sector, is found by multiplying the percentage by 360°. Download high resolution version (800x800, 12 KB)Pie chart with preliminary results from the 2004 European Parliament election. ... Download high resolution version (800x800, 12 KB)Pie chart with preliminary results from the 2004 European Parliament election. ... Download high resolution version (800x800, 18 KB)Exploded pie chart with preliminary results from the 2004 European Parliament election. ... Download high resolution version (800x800, 18 KB)Exploded pie chart with preliminary results from the 2004 European Parliament election. ... Elections to the European Parliament were held from June 10, 2004 to June 13, 2004 in the 25 member states of the European Union, using varying election days according to local custom. ...

*Because of rounding, these totals do not add up to 100 and 360. The European United Left–Nordic Green Left is a socialist and communist political grouping within the European Parliament. ... PES can refer to: Packetized Elementary Stream Party of European Socialists PES, the film director and animator Physical Employment Status, a fitness classification scheme in the Singapore Armed Forces Potential energy surface, in Physics Pro Evolution Soccer Programmed electrical stimulation, a type of electrophysiologic study Proposed Encryption Standard Psychiatric Emergency... The European Free Alliance - Democratic Party of the Peoples of Europe , EFA - DPPE is a grouping of various political parties who believe in either political independence and full statehood, or some form of devolution for their particular area. ... For the word, see Edd. ... The European Liberal Democrat and Reform Party aisbl (founded 1993) is a liberal party, active in the European Union, uniting liberal and centrist parties around Europe which together represent more than 20 million European voters and is an international non-profit association incorporated under the laws of Belgium. ... EPP may refer to: Enhanced Parallel Port (computer peripheral communication standard) The European Peoples Party (political party) Extensible Provisioning Protocol (network protocol) Extruded PolyPropylene foam. ... The Union for a Europe of Nations is a nationalist and (mostly) euro-sceptic party grouping with seats in the European Parliament. ...

The size of each central angle is proportional to the size of the corresponding quantity, here the number of seats. Since the sum of the central angles has to be 360°, the central angle for a quantity that is a fraction Q of the total is 360Q degrees. In the example, the central angle for the largest group (EPP) is 135.7° because 0.377 times 360, rounded to one decimal place(s), equals 135.7.

Discussion on use

Three sets of data plotted using pie charts and bar charts.

Statisticians tend to regard pie charts as a poor method of displaying information. While pie charts are common in business and journalism, they are uncommon in scientific literature. One reason for this is that it is more difficult for comparisons to be made between the size of items in a chart when area is used instead of length. In Stevens' power law, visual area is perceived with a power of 0.7, compared to a power of 1.0 for length. This suggests that length is a better scale to use, since perceived differences would be linearly related to actual differences. Image File history File links Piecharts. ... Image File history File links Piecharts. ... Statisticians or people who made notable contributions to the theories of statistics, or related aspects of probability, or machine learning: Peter Armitage M. S. Bartlett Thomas Bayes Yves Berger Duane Boes Ladislaus Bortkiewicz George Box Pafnuty Chebyshev Alexey Chervonenkis William Cochran (Sir) David R. Cox Richard Threlkeld Cox Harald Cram... Stevens power law is a proposed relationship between the magnitude of a physical stimulus and its perceived intensity or strength. ...

In research performed at AT&T Bell Laboratories, it was shown that comparison by angle was less accurate than comparison by length. This can be illustrated with the diagram to the right, showing three pie charts, and, below each of them, the corresponding bar chart representing the same data. Most subjects have difficulty ordering the slices in the pie chart by size; when the bar chart is used the comparison is much easier. ^[8]. Similarly, comparisons between datasets are easier using the barchart. However, if the goal is to compare a given category (a slice of the pie) with the total (the whole pie) in a single chart and the multiple is close to 25% or 50%, then a pie chart works better than a bar graph. This article needs to be cleaned up to conform to a higher standard of quality. ...

Variants and similar charts

Exploded pie chart

A chart with one or more sectors separated from the rest of the disk. This effect is used to either highlight at sector, or to highlight smaller segments of the chart with small proportions.

Perspective (3D) pie chart

An example of a three dimensional pie chart.

This style of pie chart is used to give the chart a 3D look-and-feel. Often used for aesthetic reasons, the third dimension does not improve the reading of the data; on the contrary, these plots are difficult to interpret because of the distorted effect of perspective associated with the third dimension. The use of superfluous dimensions not used to display the data of interest is discouraged for charts in general, not only for pie charts.^[9] Image File history File links FarmlandinEU2. ... Image File history File links FarmlandinEU2. ... The space we live in is three-dimensional space. ... Look up perspective in Wiktionary, the free dictionary. ...

Polar area diagram

"Diagram of the causes of mortality in the army in the East" by Florence Nightingale.

Florence Nightingale is credited with developing a form of the pie chart now known as the polar area diagram, or occasionally the Nightingale rose diagram and first published in 1858. The name "coxcomb" is sometimes used erroneously, but this was the name Nightingale used to refer to a book containing the diagrams rather than the diagrams themselves. ^[10] Image File history File linksMetadata Nightingale-mortality. ... Image File history File linksMetadata Nightingale-mortality. ... Embley Park, now a school, was the family home of Florence Nightingale. ...

The polar area diagram is similar to a usual pie chart, except that the sectors are each of an equal angle and differ rather in how far each sector extends from the centre of the circle, enabling multiple comparisons on one diagram. It has been suggested that most of Nightingale's early reputation was built on her ability to give clear and concise presentations of data.

Although Florence Nightingale is usually credited with this graphical invention, there are earlier uses. Léon Lalanne used a polar diagram to show the frequency of wind directions around compass points in 1843. André-Michel Guerry is an earlier inventor of the "rose diagram" form, in an 1829 paper showing frequency of events for cyclic phenomena
Embley Park, now a school, was the family home of Florence Nightingale. ...

History

The earliest known pie chart is generally credited to William Playfair's Statistical Breviary of 1801, where two such graphs are used.^[11][5] This invention was not widely used at first;^[5] Charles Joseph Minard being one of the first to use it in 1858, in particular in maps where he needs to add information in a third dimension.^[12] William Playfair (September 22, 1759 - February 11, 1823) a Scottish engineer and political economist, was an important inventor of statistical graphics. ... The Union Jack, flag of the newly formed United Kingdom of Great Britain and Ireland. ... Categories: Possible copyright violations ...

One of William Playfair's pie charts in his Statistical Breviary, depicting the proportions of the Turkish Empire located in Asia, Europe and Africa before 1789. Image File history File links Playfair-piechart. ... Imperial motto: unknown The Ottoman Empire at the height of its power Official language Ottoman Turkish Capital İstanbul (Constantinople) Sovereigns Sultans of the Osmanli Dynasty Population ca 40 million (at most) Area (1683) 11 955 000 km² Establishment 1281 Dissolution October 29, 1923 Currency Akçe The flag of the later... For other uses, see Asia (disambiguation). ... For other uses, see Europe (disambiguation). ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ...

Minard's map using pie charts to represent the cattle sent from all around France for consumption in Paris (1858). Image File history File links Size of this preview: 600 × 600 pixelsFull resolution (1000 × 1000 pixel, file size: 1. ... This article is about the capital of France. ...

Notes

1. ^ Cleveland, p. 262
2. ^ Wilkinson, p. 23.
3. ^ Tufte, p. 178.
4. ^ van Belle, p. 160–162.
5. ^ ^{a b c d} Spence (2005)
6. ^ Good and Hardin, p. 117–118.
7. ^ Tufte, p. 44
8. ^ Cleveland, p. 86–87
9. ^ Good and Hardin, chapter 8.
10. ^ Florence Nightingale's Statistical Diagrams. Florence Nightingale Museum. Retrieved on 2006-11-21.
11. ^ Tufte, p. 44
12. ^ Palsky, p. 144–145

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 325th day of the year (326th in leap years) in the Gregorian calendar. ...

References

• Cleveland, William S. (1985). The Elements of Graphing Data. Pacific Grove, CA: Wadsworth & Advanced Book Program. ISBN 0-534-03730-5. 
• Good, Phillip I. and Hardin, James W. Common Errors in Statistics (and How to Avoid Them). Wiley. 2003. ISBN 0-471-46068-0.
• Guerry, A.-M. (1829). Tableau des variations météorologique comparées aux phénomènes physiologiques, d'aprés les observations faites à l'obervatoire royal, et les recherches statistique les plus récentes. Annales d'Hygiène Publique et de Médecine Légale , 1 :228-.
• Harris, Robert L. (1999). Information Graphics: A comprehensive Illustrated Reference. Oxford University Press. ISBN 0-19-513532-6. 
• Palsky Gilles. Des chiffres et des cartes: la cartographie quantitative au XIXè siècle. Paris: Comité des travaux historiques et scientifiques, 1996. ISBN 2-7355-0336-4.
• Playfair, William, Commercial and Political Atlas and Statistical Breviary, Cambridge University Press (2005) ISBN 0-521-85554-3.
• Spence, Ian. No Humble Pie: The Origins and Usage of a statistical Chart. Journal of Educational and Behavioral Statistics. Winter 2005, 30 (4), 353–368.
• Tufte, Edward. The Visual Display of Quantitative Information. Graphics Press, 2001. ISBN 0961392142.
• van Belle, Gerald. Statistical Rules of Thumb. Wiley, 2002. ISBN 0471402273.
• Wilkinson, Leland. The Grammar of Graphics, 2nd edition. Springer, 2005. ISBN 0-387-24544-8.

Oxford University Press (OUP) is a highly-respected publishing house and a department of the University of Oxford in England. ... Edward Rolf Tufte (IPA /ˈtʌf. ...

See also

• Pro-rata

Another name for the top down approach to emissions estimations in air quality management. ...

External links

Wikimedia Commons has media related to:

Pie chart

• Warning against using pie charts
• Pie Charts, on Edward Tufte's "Ask E.T." forum.
• Polar area diagram, on Edward Tufte's "Ask E.T." forum.