Median voter theorem

The median voter model is used in the (new) political economics ( = economic theory of politics ) to illustrate the behavior of the parties. From the model it can be concluded that the positions of the parties will ultimately converge towards the center.

Assumptions

This model is based on the illustration of a two-party system; a party is more than the left, the other classified as rather right. Also is simply assumed that voters can be classified in polls in two spectra, left and right. Between an extreme left position of a selector and an extreme right a continuous gradation is possible.

Idea

Voters whose political and ideological views are left of the left-wing party will choose the left-wing party, as they are better served by it. Conversely, voters whose views are to the right of the right-wing party, choose the right party. These edges have the two parties in their statements do not take into account the votes have them to some extent already secure.

The median voter model therefore assumes that during the election campaign, the positions of the political center are particularly competitive. Shift the left party programmatically closer to the right party approach so they can decrease these votes. Conversely, the right-wing party will seek to continue to move to the left. There will be a fight for the middle. The decisive for the election voters in the middle is called median voter.

The phenomenon is amplified by assuming an approximately normal distribution of voters classification, as this in the middle especially many votes are to pick up.

Double median voter model

The described model is extendable to the effect that in left-wing parties rather right top candidates are established and reversed in right-wing parties rather left. In this way one expects a better chance to win the median voter votes. On the voters on the edge a little care must be taken, as these are already choose them closer standing candidates. Promising therefore is only the struggle to win over the center. Only this can be obtained by the choice of the candidate.

In this way is explained why prevail in social democratic parties often belonging to the conservative wing candidates in conservative parties, however, often candidates who belong to the social wing. The positions of the top candidates are therefore often less far apart than the positions of the parties themselves, it act " centripetal forces " of political competition.

History

The median voter model was first described in Duncan Black's article On the Rationale of Group Decision -making in 1948. Distribution found it especially by Anthony Downs ' book An Economic Theory of Democracy (1957). First approaches to the model can be found, however, already in Condorcet (later generalized by Kenneth Arrow ), and especially in 1929 in the essay Stability in Competition by Harold Hotelling. For this reason, the median voter model is sometimes called Hotelling - Downs model.

Assessment

Sometimes there is criticism that the model can be directly applied only in the two-party case. Also corresponds to a reduction to the "left" and "right" not the political reality can be distinguished between the socially liberal and socially conservative, economically liberal and regulatory friendly, ecology -friendly and technology- friendly, and many other positions.

However, this is at least analytically no problem, because you can apply to other dimensions of the coordinate system, the positions of the other parties. For example, one would then ecology friendly ecology hostile obtained with the axis of a two-dimensional coordinate system in which the same considerations are possible in principle. Multidimensional ( especially more than three-dimensional ) coordinate systems are less well represented graphically, however, explain the situation also.

Conclusion

Despite the simplifying assumptions of the model can be based on his crucial explanations for the behavior of parties in a political system gain. This is especially true for two-party systems. This allows the predictions of the model in such systems often observe about in election campaigns in the United States.

However, the model can in principle be extended to multi-party systems, such as in Germany. This is also because there is often also in multi-party systems, only the selection of two political camps, or by polarization in the election campaign, this impression is conveyed. Experience has shown that the neglect of wings can lead to spin-offs and start-ups of parties, either because problem areas have been neglected ( Social Policy → Social parties, ecology → Environment parties, freedom of information → Privacy parties ) or ideologies were not served. This is the case if the parties to align their positions on the very middle and neglect the edges. In this way, a two-party system be expanded to a multi-party system.