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Casting a Condorcet ballot

Your ballot

Before anything else, let's have a look at how the ballot will look like when taking part in a condorcet poll.


Whom would you prefer to be your class delegate?
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Pairwise Election

You want to take part in a condorcet election. When you have the ballot in your hands or on the screen, remember that with Condorcet what you are actually taking part in many elections, as many as necessary so that each candidate can face any other candidate individually.

Imagine the following polling question:


Imagine you have a new born baby girl. Choosing from the following list, how would you prefer naming her?
  • Jean
  • Mary
  • Jennifer
  • Susan
  • Diana
  • Wendy
  • Michelle

In Plurality voting, you can choose only one name, which may be just as well because your daughter would need only one. But suppose that the purpose of the poll is to find out which names are popular: you may like more than one name. With Approval voting, you can tick several names in the list. If, however, we want to have a ranking of the names from the most popular to the least popular. In a condorcet poll, you can state your exact preferences, as if you were to answer all of the following questions:


In the following sets of two names, which one do you prefer?

Names Tick one
Tick 'none' if you have no preference.
A B  A   B  None
Jean Mary
Jean Jennifer
Jean Susan
Jean Diana
Jean Wendy
Jean Michelle
Mary Jennifer
Mary Susan
Mary Diana
Mary Wendy
Mary Michelle
Jennifer Susan
Jennifer Diana
Jennifer Wendy
Jennifer Michelle
Susan Diana
Susan Wendy
Susan Michelle
Diana Wendy
Diana Michelle
Wendy Michelle

A ballot like this would be easily understood by anyone. The problem is that the number of rows in the ballot can grow rapidly according to the number of candidates. With 7 candidates (7 names to choose from), we take part in 21 pairwise elections (6+5+4+3+2+1=21). There is an ongoing poll in the Agora for the US 2004 presidential election which has a whooping 45 candidates. The ballot is quite a handfull as it is, but if we were to list all of the pairwise elections in that Condorcet poll, we would have a ballot with 1035! lines. This election is admitedly rather extreme by the number of its candidates. Our poll above, with seven female names, would nicely fit in a ballot with... 7 lines only!

Casting a Condorcet ballot

A blank ballot

Imagine you are now a Pom-Pom girl and you have to select your group leader. This would be how the ballot would look like in your group's phpBB forum:


Whom do you want to elect as your Pom-Pom group leader?
View Results

You can click on the pull down menus above, to test a bit.

Ranking the candidates

In your ballot, the order (1,2,3...) is already pre-selected. You can therefore concentrate on ranking all the candidates, starting from your favorite one at the top and going down to your least favorite.

The ballot design is flexible enough to allow you to adjust the rankings, in case there are some candidates that you wish to rank equally. The vote bellow doesn't show any preference between Wendy and Michelle nor between Mary and Diana.


Whom do you want to elect as your Pom-Pom group leader?
View Results

If Susan is your best friend and your kindred spirit, you'd rank her first, Jennifer being a good second choice. If both fail to be elected, then you'd still be happy with either Wendy or Michelle as your leader. Jean is a newcomer: you don't know her very well, so you give her the benefit of the doubt. On the other hand, you positively dislike Mary and Diana, whom you rank last, accordingly!

Relativity

The ballot below is perfectly identical to the one above, even though the rankings have been somewhat modified. What matters, is the relative position of the candidates. For example, it doesn't matter a bit whether you rank Wendy and Michelle third or fourth. What matters is that they have the same ranking (i.e. they are both third or both fourth) and that they both loose to Susan and Jennifer but win against the other three candidates.


Whom do you want to elect as your Pom-Pom group leader?
View Results

Leaving a candidate out

You don't have to enter all the candidates into your ballot. It's perfectly ok to leave some candidates out as in the example below. It is however recommanded that you leave only the candidates (or, in this case, the dishes) that you know but dislike. Do enter the candidates (dishes) you don't know so that they get a higher ranking than the ones you don't like. After all, it's not because you've never eaten such dishes that they taste bad. It would be the same for not so well-known political candidates: give them the benefit of the doubt. If they get a higher ranking than the candidates you don't like, by the next election they may have more media exposure and you'd be able to make a more informed choice.


Which of these dishes do you prefer?
View Results

In our example, the voter likes Chinese food and especially dumplings but doesn't like Stinky tofu. As you can see if you pull down the menus (pun non intentional), the voter wouldn't like to eat any of the three dishes left out: Pizza, Hamburger and Stinky Tofu. The voter probably doesn't know what Bouillabaise is: it may taste good or bad. It is ranked lower than the dishes he likes but higher than the dishes left out. It doesn't matter if Bouillabaise is ranked fourth or seventh in this example. It is as if the remaining three dishes were ranked last, i.e. eighth.

This page is situated at http://www.masquilier.org/libre/phpbb/condorcet-ballot.php

It has been last updated on: 23 Aug 2004

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