Referendums have been held in Australia to approve parliament-proposed changes to the Constitution of Australia or to the constitutions of states and territories. Polls conducted on non-constitutional issues are sometimes but not always referred to as plebiscites. Not all federal referendums have been on constitutional matters (such as the 1916 Australian conscription referendum), and state votes that likewise do not affect the constitution are frequently said to be referendums (such as the 2009 Western Australian daylight saving referendum). Historically, they are used by Australians interchangeably and a plebiscite was considered another name for a referendum. Voting in a referendum is compulsory for those on the electoral roll, in the same way that it is compulsory to vote in a general election. As of 2020, 44 nationwide referendums have been held, only eight of which have been carried. Since multiple referendum questions are often asked on the same ballot, there have only been 19 separate occasions that the Australian people have gone to the polls to vote on constitutional amendments—of which have 8 been concurrent with a federal election. There have also been three nationwide plebiscites (two on conscription and one on the national song), and one postal survey (on same-sex marriage). Federal referendums Constitutional provisions Section 128 of the Constitution specifies that alterations to the Constitution cannot be made without a direct public vote. A bill containing the amendment must first be passed by both houses of parliament or, in certain limited circumstances, by only one house of parliament. If the bill has only been passed in one house, the Governor-General must, under the "deadlock provision" of section 128, then decide whether or not to submit the referendum to the people. By convention, this is done on the advice of the Prime Minister. Since the Prime Minister normally controls the House of Representatives, the effect of this convention is to make it virtually impossible for a referendum to be put to the people if approved by the Senate, but not the House. If the bill to alter the Constitution is approved by both houses or satisfies the deadlock provision, the bill is submitted to the electors for approval. The referendum is conducted according to the Referendum (Machinery Provisions) Act 1984. If the bill is approved by an absolute majority of both houses, the Constitution provides that it must be submitted to the electors no less than two months but no