Political parties, candidates
and media conduct polls (surveys) gauge voter support for the different
candidates or parties. Polls are also used to focus campaigns and to develop
and improve messages for voters. When the results of a poll are announced
publicly, the methodology used should generally be made public so that users
may assess the accuracy of the poll. In Canada,
this information includes the names of whoever conducted and commissioned the
poll, the timing of the poll, the sample population, the number of people
contacted, the margin of error for the results presented, the wording of
questions asked, and instructions on how to obtain more detailed information on
methodology.
The timing of the release of
poll results may be an integrity issue. The results of an opinion poll may
influence undecided voters and create momentum in favour of a candidate. Thinking
that the election has already been decided may cause people to choose to refrain from
voting.
To avert such problems, some
systems prohibit the release of poll results within a certain time period, usually
immediately before election day. These rules may vary; in Mexico,
for instance, it is an offence to release a poll predicting the winner less
than eight days before voting ends. In Canada the law
prohibits the publication of opinion poll results during the last three days of
the electoral campaign, while in Denmark
there is no restriction on the publication of polls.
