In slightly more economical terms, a rational voter would choose
to vote when the expected money value of the difference between
the candidates' election minus the probability that his vote will
influence the election is greater than the opportunity cost of
voting. So, why do people vote if the gain from an election is
required to be so high? You might then think that elections would
have no voters. The answer relies on the fact that there are sociological factors: ethical values,
civic duty, indoctrination, or social pressures, etc… which
economists don't usually take into account. These are harder to
measure for. But it is quite obvious that these sociological factors
must be quite large and have strong influence over the other factors
if a person is to vote.
Furthermore, any individual voter's choice to improve decision-making
depends on a number of factors. A single voter's incentive to
devote time to improving his knowledge depends on what he believes
his profit will be from voting after the learning has occurred.
If this were negative he wouldn't want to spend his time doing
it. The larger the elections, the less time and energy that will
be spent trying to improve his knowledge. The thing is that people
still vote even when they are uniformed. This is because the sociological
factors may outweigh an individual's loss from voting. Of course
being uninformed leads to inefficiencies. And because of the "free
rider" problem and the "public good" nature of
information, even if information is made available, it is available
and supplied in inefficiently small quantities.
What does all of this imply about the efficiency of democracy
as a means of causing public goods to be supplied? Basically,
regarding social or moral obligations, people differ. Some people
are sensitive to what they believe are the opinion of others and
others are not. Some vote because "it is the right thing
to do," others don't vote because they like to go against
what they are told to do, others just do it because it is a habit…
others vote if the personal gains are greater than the personal
costs of not voting, and still others never even think about voting.
Because of such an assortment of voter characteristics, we would
not expect the candidates who are ultimately chosen for office
to perfectly represent a cross section of the eligible voters.
To understand this a bit better this consider the following example:
There are 2 candidates, Candidate X & Y. Candidate X barely
wins the elections. Suppose that all of his votes came from voters
who just felt a moral obligation to vote despite that they had
less information about the candidates than the other voters or
non-voters. On the other hand, Y receives all the votes of the
voters who pay no attention to sociological factors. Moreover
a survey of only non-voters shows that Y is their overwhelming
favorite. We would surely be wrong then to assume that the election
of X best represents the preferences of the collective as a whole.