A referendum, plebiscite or ballot measure is a vote on a proposal, law, or political issue by citizens (rather than their elected representatives). Referendums can be binding (resulting in the adoption of a new policy) or advisory. In the US, they are known as state and local referenda.
A number of countries use referendums, particularly for constitutional changes. These include Ireland, Switzerland, Denmark, and Australia, as well as 49 of the 50 U.S states. Referendums can also be used for non-constitutional issues, such as a change in voting system or the national anthem. Some governments combine a referendum with an election to make it easier for voters to understand and decide on the issue. However, critics argue that combining the votes can distort the outcome.
Surveys show that one of the biggest problems with referendums is a lack of information. This is especially true for those that are government-initiated. In these cases, the governing party may have an interest in framing the question to increase the likelihood of its desired outcome.
Voters seeking information to help them reach a decision will look for cues from their political parties, prominent opinion leaders, and groups and organizations involved in the campaign. These cues are often sufficient to change voter opinions, but if a voter has already strongly held predispositions or is unfamiliar with the issue, campaign information can have little influence. In addition to providing information, referendums must also determine how the result will be determined. Most referendums are conducted using simple majority voting, but if the outcome is a close call, alternative methods such as proportional representation or instant runoff voting (IRV) may be employed.