I want to run a vote to pick favorite video games, but I think this applies to many other voting domains.

The scenario is people rank games they like from favorite to least favorite. I would like to find a community aggregate list of favorites ranked from most to least favorite. The problem is that, given a list of candidates, most people have not played all of them and will only rank the games they have played.

An example forum where people are ranking games.

I would like a ranked-ballot system that considers un-ranked candidates as having no preference and generates a ranked list of results.

I am using a Condorcet voting site that has many voting system options: https://www.condorcet.vote/Vote/D990CF0F78/Admin/EB81B7CD77/

  • Without reference to a specific system I think this is too broad. You're basically asking for a compare and contrast reference article. – Jontia Aug 12 '19 at 15:17
  • My understanding is that, if there is a true Condorcet winner, the unranked candidates are not penalized. The problem comes in when there is not a Condorcet winner. The Condorcet Method Wikipedia page says: Usually, when a voter does not give a full list of preferences they are assumed, for the purpose of the count, to prefer the candidates they have ranked over all other candidates. – chadum Aug 12 '19 at 15:20

Score based systems can be designed so as not to penalise unranked options. For example, "Voters score each candidate between -5 and +5, unranked candidates count as zero"

It is possible to convert a ranking system into a scoring system. For example you might assign scores of +0.5 to strawberry and -0.5 to vanilla. There are many ways of doing this, but all have problems. If you assign scores in such a way that the mean score is zero, you can then assign 0 to all the unranked items. The result is then found by summing the scores.

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This is not a characteristic of the system. This is a characteristic of the implementation. For example, in Instant Runoff Voting/Alternative Vote (IRV/AV), you could create a default level and put it in the middle. Then your ballot might look like

  • Jill Stein
  • Hillary Clinton
  • Default
  • Gary Johnson
  • Donald Trump

I'll leave it up to you whether this ranks from the bottom or the top (i.e. is Trump first and Stein last or is Trump last and Stein first). But the unranked candidates would be between Clinton and Johnson in this example.

Or you could implement IRV/AV where the default candidates are always last. Same system but two different implementations.

It's common for Condorcet-compliant systems to ignore candidates left out of the rankings. They simply don't get a pairwise count. But this is not a systemic requirement. You can count them last if you want.

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