Lesson 3 of 8
In Progress

Other Considerations and Constraints on Voting Methods

Roy Minet October 17, 2022

In our real world, no voting method is able to utilize a satometer to reach into voters’ brains and extract their sincere satisfactions and dissatisfactions for candidates.  Unfortunately, the only way a real voting method has to obtain any data from voters is to ask them for it.  That is a serious problem.  There is no guarantee that voters will provide correct data.  Voters can and do lie a lot.  If a voter believes (correctly or incorrectly) that indicating something other than their sincere opinions about the candidates will enable their ballot to have a greater impact on the election outcome in some way that they would prefer, they will not hesitate to lie.  This is called insincere or strategic voting.

The Gibbard-Satterthwaite Theorem (as extended) It has been proven that any voting method (other than a dictatorship) can be manipulated to some extent by strategic voting.  No voting method can be completely immune to such disruption, but some are much more susceptible to it  than others.  This must be a consideration when designing or selecting a voting method.

Noise As previously mentioned, there is bound to be some fraction of voters who are, uninformed, careless or for whatever reason, unable to provide data which is useful and helpful to selecting the correct winner.  Such “noise” is one more impediment to identifying the best winner with which real-world voting methods must contend.

This means that, unfortunately, designing or choosing the best real-world voting method is always a tradeoff that must consider a method’s vulnerability to strategic voting and noise or garbage inputs from voters.

The Jones Rule So named for Douglas Jones (U. of Iowa, Computer Science Dept.) who stated it so succinctly, the Jones rule says that “Anything about elections must be understandable by a reasonably bright high school student.”  Of course, that covers more than just the voting method, but it certainly does include the voting method.  If how elections work is a deep mystery, voters may suspect that “a man behind a curtain” may be manipulating the results.  And in fact, there could be a man behind a curtain manipulating the results.  Under such circumstances it will be difficult or impossible for everyone to implicitly trust their elections, which of course, is a very important requirement.  Also, no politician should vote to authorize the use of an election mechanism that s/he doesn’t understand.

Designing or choosing a very good voting method may at first seem like a fairly simple problem.  However, it should by now be apparent that the problem is a whole lot trickier than it may appear to be.  That is why the quest for a great voting method has gone on for 250 years, and only recently has rapid progress been made toward a full understanding of the problem.

Responses

  1. That note about the fact that any voting method can be manipulated is a critical one when talking about why First Past the Post is the worst system around — it’s manipulated by fracturing the electorate!