[EM] Method definitions

Markus Schulze schulze at sol.physik.tu-berlin.de
Tue Mar 7 16:35:56 PST 2000


Dear Blake,

in his paper "Sur la Forme des Elections" (1789),
Condorcet proposes a Copeland method. He writes:

> S'il y a seulement vingt Concurrens, pour avoir le
> resultat de leur comparaisons deux a deux, il faut
> examiner les voix donnees sur 190 propositions, et
> sur 780 propositions s'il y a 40 Concurrens. Souvent
> meme ce resultat ne seroit pas satisfaisant qu'on
> pourroit le desirer; car il peut arriver qu'aucun
> Concurrent ne soit declare superieur a tous les autres
> par la pluralite, et alors on est oblige de preferer
> celui qui est seulement juge superieur a un plus grand
> nombre; et parmi ceux qui seroient juges superieurs
> a un egal nombre de Concurrens, celui qui seroit juge
> ou superieur par une plus grande pluralite ou inferieur
> par une moindre. Mais il se presente des cas ou cette
> preference est difficile a determiner, les regles
> generales seroient compliquees, embarrassantes dans
> l'application. Ainsi cette forme d'election ne convient
> gueres que pour les choix qui peuvent etre differes, a
> moins que l'on ait un moyen prompt d'appeler de nouveaux
> Electeurs lorsque la question est restee indecise,
> encore ce dernier moyen n'assure-t-il pas le succes, et
> ne fait que le rendre plus probable.

My own translation:

> If there are only 20 competitors then -to get the result
> of their head to head comparisons- it is necessary to
> evaluate the votes for 190 propositions, and for 780
> propositions if there are 40 competitors. Very often
> even this result isn't as satisfying as you might
> want it to be; it can happen that no competitor is
> declared superior to all the others by the plurality,
> and thus you have to prefer that one who is considered
> superior to the largest number; and amongst those
> who are considered superior to an equal number of
> competitors, that one who is considered superior by
> the largest plurality or inferior by the smallest. But
> there are situations where this preference is difficult
> to determine and where the general rules can be
> complicated and embarrassing. Therefore this election
> method can only be used for distinguishable choices
> or for situations where you can appeal to new
> voters immediately whenever the question couldn't
> be answered. And even if this appeal cannot
> guarantee a success, it makes it more probable.

To my opinion, this quotation demonstrates that Condorcet
rather promotes a family of election methods than one
single election method.

Markus Schulze
schulze at sol.physik.tu-berlin.de
schulze at math.tu-berlin.de
markusschulze at planet-interkom.de



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