13 March 2019

Voting Systems

Ranked Choice (RC) vs Instant Runoff (IRV) vs Approval

RC and IRV are technically different. RC is a way of expressing preference, IRV is a method of tabulating votes from RC ballots.

This is an important distinction.

IRV, which seems pretty good can solve one problem (e.g. Gore v Bush) but introduce others. Technically IRV is nonmonotonic. That is, a shift of public opinion toward a candidate can cause that candidate to lose, and a shift of public opinion away from a candidate can cause that candidate to win.

A different and probably superior method is one called Condorcet. It eliminates most of the IRV issues but introduces a few other, but less likely, issues. IRV is to Condorcet as single elimination is to round robin.

Superior to both of them is Approval voting, in which you select all candidates that would be acceptable to you. It’s simple to tabulate and does not have the issues of either IRV or Condorcet.

There’s a website that has wonderful graphics of how these different systems can work or not depending on the positions of the candidates. http://zesty.ca/voting/sim/

The author of the site is Ka-Ping Yee.

Our election method makes it virtually impossible for third parties to gain a significant foothold. The electoral system is an added complication for presidential races, but the same holds true for state and local races as well as primaries with crowded fields.

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