Since 1970, the South Australian House of Assembly (the "lower house") has consisted of 47 single-member electoral districts consisting of approximately the same number of enrolled voters. The district boundaries are regulated by the State Electoral Office, according to the requirements of the South Australian Constitution and are subject to mandatory redistributions by the State Electoral Office in order to respond to changing demographics.
Electoral boundaries are adjusted after each election. The primary consideration is to attempt to ensure that the party that obtains 50% or more of the overall vote at a general election is able to form a government. The number of electors in each district must be within 10% of the average at the time of the redistribution order. After these primary considerations, other issues are considered, including economic, social and regional communities of interest. Despite this elaborate and expensive process, the system is not particularly reliable; cases where the party forming government has received less than 50% of the two-party-preferred vote are not un-common, and have occurred in two of... Read More