Tactical Voting Can Be a Weak Strategy

Tactical voting is probably overvalued by millions of would-be rational voters in first-past-the-post elections. These citizens suffer losses in individual representation, and the political systems they participate in will tend to lose the strengths of democracy to the weaknesses of mob psychology.

The value of a vote

Given that the overarching goal of the rational voter is to shape public policy to conform as closely as possible to his preferences, his net expected utility might be defined as the sum of three factors, which we'll call the Immediate-Election Utility, the Policy-Shift Utility, and the Future-Election Utility. To increase the net expected utility, a vote must either increase a more favorable candidate's chances at the expense of a less favorable opponent, or cause any candidate to become more favorable, so each of the three factors ought to achieve at least one of these effects.

Immediate-Election Utility

The expected Immediate-Election Utility is determined by the desirability of the candidates' policies (or, more accurately, the desirability of the policies that will be successfully enacted by the candidate) weighted by their respective chances of victory in the current election.

The probability distribution of large elections is generally very broad; consequently, even in very "close" races, the chances that an individual's vote will be the deciding one is very small. And as far as a given election is concerned, only a deciding vote has any utility for the voter. However, the Immediate-Election Utility of voting for a compromise candidate is often greater than that of voting for a preferred candidate.

Policy-Shift Utility

The expected Policy-Shift Utility is determined by the effect a vote will have on the policy positions of the various parties, making their respective candidates more or less favorable. A vote is the strongest indicator of voter preference, and the best predictor for behaviour in future elections. Competing parties will tend to shift policies to capture votes. A vote cast for a compromise candidate could have a negative marginal Policy-Shift Utility, since it attracts all parties toward the compromised policies rather than toward the preferred policies.

Furthermore, in cases where the Immediate-Election Utility of a compromise vote is highest (close races), the Policy-Shift Utility of a true-preference vote is also high. Parties in close competetion have more need to capture votes, so a true-preference vote would have more policy-shifting utility.

Future-Election Utility

The expected Future-Election Utility is determined by the effect a vote will have on future election results. A vote for a party will contribute to an informational cascade of three parts:
  • It will increase recognition of the party (this yields diminishing returns for larger parties, until it becomes negligible), which will help some voters discover the party as their true preference.

  • It will increase the respectability of the party. Voters with limited information on the various policies and related consequences of their choices will draw some information from the expressed preferences of others.

  • It will increase the recognized viability of the party. The expected utility of voting for the party will increase for other voters.

Common miscalculations

Tactical voters often only consider the Immediate-Election Utility of their votes. Furthermore, they grossly overestimate the Immediate-Election Utility when they believe that a non-deciding vote cast for the winner was valuable and meaningful whereas a vote cast for a loser is wasted. A non-deciding vote always can be considered wasted in the scope of Immediate-Election Utility.

Major political parties have an interest in discouraging voters from considering anything but Immediate-Election Utility, thus encouraging tactical voting and characterizing some votes as "wasted."

Voters may also more easily appreciate the concrete benefits of maximizing Immediate-Election Utility, in contrast with Policy-Shift Utility which relies on rational action by the major parties, and Future-Election Utility which is chaotic.


Anonymous said...

Indeed, election candidates have played scandously upon the "useless vote," making a vote not spent on the obvious out to be a pebble trying to withstand the tide. It has nullified a great deal of the population in regard to the polls--and they, acting in force (though not in concert), as it were, do indeed have no positive influence--bolstering their opinion, however irrationally, that their votes (never even cast) are indeed useless.

3:45 PM  

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