Secrets of Antony Green: Calculating notional margins for electoral redistributions

Every few years, federal and state electoral commissions conduct boundary redistributions, where the borders of electorates in a state are redrawn, either to reflect a change in the number of seats in the parliament, or to standardise the number of electors in each district.

When a redistribution occurs, electoral analysts use the results from the previous election to estimate what the results would have been had the new boundaries been in place at that election. The two-candidate-preferred margins can change significantly, and seats can even be notionally held by another party.

This presentation will show how the ABC's Antony Green and other psephologists use geographic and electoral data to calculate new electorate profiles following a redistribution, using real examples from previous elections and redistributions.

Presentation type: Full length
Session: Data Matters


Alex Lum

Alex Lum has been an editor on Wikipedia since 2005, an administrator on the English Wikipedia since 2008, and a prolific contributor to OpenStreetMap and Wikidata. He has produced results tables for every Australian election in the last five years, as well as maps of results and electoral districts, for Wikipedia's election articles. Alex is representing Wikimedia Australia, the official national chapter of Wikimedia that supports libraries, education and cultural organisations to improve the coverage of Australian content and sources in Wikipedia and related projects.