Of course, there are other problems that can arise in using majority rule as a decision making procedure, but I thought this aspect of it was non-obvious and fascinating.
Let us assume that after hearing all of the evidence in a case that the probability of a judge reaching the correct verdict regarding the accused’s innocence is 0.6. Obviously in trials presided over by one judge, the correct verdict will be reached 60 percent of the time.
A tribunal that employed the unanimity rule would make the correct decision only 21.6 percent of the time. On the other occasions it would either fail to reach a unanimous verdict or would unanimously reach the wrong verdict.
If, however, the tribunal used the simple majority rule, it would always reach a verdict, and would reach the correct verdict 64.8 percent of the time. Moreover, the probability that a panel of judges reaches the correct verdict grows continuously as its size increases – provided that it employs the simple majority rule.
-- Mueller, p. 128-129
One of the biggest detriments of using majority rule for political decision making is tyranny of the majority. A good political institution should use a variety of rules with more concensus being required for weightier decisions.
I am thoroughly enjoying this Public Choice class so far and it is getting me to look at political institutions and decision making in an entirely new light.
It has also been a tremendous opportunity to listen to lectures by two of the chief architects of this school of thought while here at GMU -- Gordon Tullock and Nobel Laureate James Buchanan. In addition to being here at GMU, something else I share in common with these two great scholars is that we've all three done our time at the magnificent Virigina Tech.
Read more on Condorcet's jury theorem here.
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