# Social Choice

*Social Choice* theory studies the ways of mapping individual preferences expressed by *preference ballots*, i. e. ordered lists of alternatives, (columns in the applet) into a selection of one or ranking of several such alternatives.

The applet presents four methods: *Plurality*, *Borda*, *Plurality with Elimination*, and *Pairwise Comparison* of alternatives.

(Bold numbers could be clicked upon. To increase the number, click to the right of its vertical center line. To decrease it click to the left of the line. Dragging the mouse near the center line will accomplish the same task, but faster. Small triangles in the upper right corner of the cells allow swapping adjacent cells contents, thus adjusting the ballots.)

What if applet does not run? |

(A newer version of the applet is also available online at https://www.cut-the-knot.org/Curriculum/SocialScience/Voting.shtml. The later version has no direct way for method comparison, but has the advantage of letting on follow the progress of each method setp by step.)

### Reference

*For All Practical Purposes*by COMAP, 5^{th}edition, W. H. Freeman & Company, 2008 (8th edition)- G. Szpiro,
*Numbers Rule: The Vexing Mathematics of Democracy, from Plato to the Present*, Princeton University Press, 2010. - P. Tannebaum & R. Arnold,
*Excursions In Modern Mathematics*, 7th edition, Prentice Hall, 2009

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Copyright © 1996-2018 Alexander Bogomolny

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