Electoral redistribution

Redistribution is the process, used in many Commonwealth countries, by which electoral districts are added, removed, or otherwise changed. Redistribution is a form of boundary delimitation that changes electoral district boundaries, usually in response to periodic census results. Redistribution is required by law or constitution at least every decade in most representative democracy systems that use first-past-the-post or similar electoral systems to prevent geographic malapportionment. The act of manipulation of electoral districts to favour a candidate or party is called gerrymandering.

In Australia, redistributions are carried out by independent and non-partisan commissioners in the Commonwealth, and in each state or territory. The various electoral acts require the population of each seat to be equal, within certain strictly limited variations. The longest period between two redistributions can be no greater than seven years. Many other triggers can force redistribution before the chronological limit is reached. The redistribution is drafted by civil servants.

In Canada, the constitution mandates that redistribution occur "on the completion of each decennial census." District boundaries are based on electoral quotients, with some exceptions. When the census indicates that a population change has occurred, an independent boundary commission issues a report of recommended changes. Changes are only made if passed into law—by Parliament for national redistribution, by the provincial legislature for provincial redistribution.

India has an established process to redistribute its legislative districts. Redistributions are approved by political appointees to the Boundary Commission of India.

Elections to Dáil Éireann and to councils and local authorities are by single transferable vote (STV), using geographic constituencies which return three or more representatives. The number of representatives for each district is proportional to population. Boundary revisions may involve changing the number of constituencies, reapportioning the number of representatives returned from them, or adjusting the constituencies' borders. For example, the Electoral (Amendment) Act of 2005 replaced the five-seat Meath constituency with two three-seat constituencies, Meath East and Meath West, both of which also acquired territory previously in other constituencies.

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