Saturday, March 6, 2010

Start Learning About The Borda Count, Ctd

I received a great comment on my previous post about the Borda count, which is an alternative voting system that I believe is superior to the current plurality-rule regime.  Anthony writes:

"A very interesting idea, but I wonder how well it would work in our two-party system. The Wikipedia page states that the Borda count "affords greater importance to a voter's lower preferences than most other systems." I am imagining a scenario where the two major party candidates roughly divide the As (borrowing your GPA analogy), but due to the binary (yes/no) mentality within the two-party system voters are unwilling to give their B votes to the candidate of the opposing party. If an independent candidate receives only 5% of the As, but ends up with 90% of the Bs, could he/she steal the show?"

The independent candidate could potentially win despite having few first-ranked votes, although it would be very close.  This scenario reflects the Borda count's biggest weakness: it may sometimes fail to elect the candidate who wins a simple majority.  This fact cuts to the core ideological argument of what bias we want our voting system to have.  No voting system is neutral; majority and plurality rules give an advantage to extreme, divisive candidates, while the Borda count favors moderate, consensus candidates.  No doubt the optics of selecting a winning candidate who was ranked first by a tiny minority would require some adjustment, however.  As for our two-party system, it exists largely because of our plurality-rule regime; adopting the Borda count would result in a more varied party system.

Anthony raises another interesting feature of voting: strategy.  In the above example, partisan voters may insincerely push a candidate further down in their ranking to increase the probability of their favored candidate winning.  While strategic voting may still occur under the Borda count, it's effectiveness is drastically reduced compared with strategic voting under plurality rule.  Instant-runoff voting is a rule designed to solve this burying problem.

1 comment:

  1. So I wonder why instant runoff voting (IRV) has gotten such play compared to the Borda count? Here in Minnesota, for example, we have Minneapolis using it for its Park Board elections, and just in the past 3 weeks there have been three op-eds in the Star Tribune about IRV (pros and cons).