political science Political science is the scientific study of politics. It is a social science dealing with systems of governance and Power (social and political), power, and the analysis of political activities, political philosophy, political thought, polit ...

and

social choice theory Social choice theory is a branch of welfare economics that extends the Decision theory, theory of rational choice to collective decision-making. Social choice studies the behavior of different mathematical procedures (social welfare function, soc ...

, the spatial (sometimes ideological or ideal-point) model of voting, also known as the Hotelling–Downs model, is a

mathematical model A mathematical model is an abstract and concrete, abstract description of a concrete system using mathematics, mathematical concepts and language of mathematics, language. The process of developing a mathematical model is termed ''mathematical m ...

of voting behavior. It describes voters and candidates as varying along one or more

axes Axes, plural of ''axe'' and of ''axis'', may refer to * ''Axes'' (album), a 2005 rock album by the British band Electrelane * a possibly still empty plot (graphics) See also * Axis (disambiguation) An axis (: axes) may refer to: Mathematics ...

(or dimensions), where each axis represents an attribute of the candidate that voters care about. Voters are modeled as having an ideal point in this space and preferring candidates closer to this point over those who are further away; these kinds of preferences are called single-peaked. The most common example of a spatial model is a political spectrum or compass, such as the traditional left-right axis, but issue spaces can be more complex. For example, a study of German voters found at least four dimensions were required to adequately represent all political parties. Besides ideology, a dimension can represent any attribute of the candidates, such as their views on one particular issue. It can also represent non-ideological properties of the candidates, such as their age, experience, or health.

Accuracy

A study of three-candidate elections analyzed 12 different models of voter behavior, including several variations of the impartial culture model, and found the spatial model to be the most accurate to real-world ranked-ballot election data. (Their real-world data was 883 three-candidate elections of 350 to 1,957 voters, extracted from 84 ranked-ballot elections of the

Electoral Reform Society The Electoral Reform Society (ERS) is an Advocacy group, independent advocacy organisation in the United Kingdom which promotes electoral reform. It seeks to replace first-past-the-post voting with proportional representation, advocating the si ...

, and 913 elections derived from the 1970–2004

American National Election Studies The American National Election Studies (ANES) are academically-run national surveys of voters in the United States, conducted before and after every presidential election. Although it was formally established by a National Science Foundation gra ...

thermometer scale surveys, with 759 to 2,521 "voters.") A previous study by the same authors had found similar results, comparing 6 different models to the ANES data. A study of evaluative voting methods developed several models for generating rated ballots and recommended the spatial model as the most realistic. (Their empirical evaluation was based on two elections, the 2009 European Election Survey of 8 candidates by 972 voters, and the ''Voter Autrement'' poll of the

2017 French presidential election Presidential elections were held in France on 23 April and 7 May 2017. Incumbent president François Hollande of the Socialist Party (France), Socialist Party (PS) was eligible to run for a second term, but declared on 1 December 2016 that he wo ...

, including 26,633 voters and 5 candidates.)

History

The earliest roots of the model are the one-dimensional

Hotelling's law Hotelling's law is an observation in economics that in many markets it is Rationality, rational for producers to make their products as similar as possible. This is also referred to as the principle of minimum differentiation as well as Hotellin ...

of 1929 and

Black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...

median voter theorem In political science and social choice theory, social choice, Black's median voter theorem says that if voters and candidates are distributed along a political spectrum, any voting method Condorcet criterion, compatible with majority-rule will elec ...

of 1948. Anthony Downs, in his 1957 book '' An Economic Theory of Democracy'', further developed the model to explain the dynamics of party competition, which became the foundation for much follow-on research.

References

{{reflist Voting theory Behavioral concepts

Accuracy

History

See also

Further reading

References