Psychology Wiki

Assessment | Biopsychology | Comparative | Cognitive | Developmental | Language | Individual differences | Personality | Philosophy | Social |
Methods | Statistics | Clinical | Educational | Industrial | Professional items | World psychology |

Statistics: Scientific method · Research methods · Experimental design · Undergraduate statistics courses · Statistical tests · Game theory · Decision theory

A bar chart, also known as a bar graph, is a chart with rectangular bars of lengths usually proportional to the magnitudes or frequencies of what they represent. Bar charts are used for comparing two or more values. The bars can be horizontally or vertically oriented. Sometimes a stretched graphic is used instead of a solid bar.


The following example chart is based on the results of the election for the European Parliament in 2004 and in 1999. The following table lists the number of seats allocated to each party group. The results of 1999 have been multiplied by 1.16933, to compensate for the change in number of seats between those years.

Group Seats (2004) Seats (1999) scaled
EUL 39 49
PES 200 210
EFA 42 56
EDD 15 19
ELDR 67 60
EPP 276 272
UEN 27 36
Other 66 29

A bar chart visualizing the above results of the 2004 election can look like this:
(If all the values were arranged in descending order this type of bar graph would be called a pareto chart.)

This bar chart shows both the results of 2004, and those of 1999:


The bar chart is possibly the invention of the Scots engineer and economist William Playfair (1759-1823). A bar chart was used in his work The Commercial and Political Atlas (London, 1786).

See also

External links

This page uses Creative Commons Licensed content from Wikipedia (view authors).