Enrolment projections overview - WA federal redistribution

Updated: 5 March 2015

The enrolment data provided by the Australian Electoral Commission (AEC) have been prepared for the information of persons and organisations interested in the redistribution of federal electoral boundaries in Western Australia.

What enrolment data is supplied?

For the purposes of the redistribution, the AEC has made available:

  • enrolment in Western Australia as at 1 December 2014
  • projected enrolment in Western Australia at 8 February 2017.

Enrolment as at 1 December 2014 is supplied as these figures were used for the Electoral Commissioner's determination of the current enrolment quota under section 65 of Commonwealth Electoral Act 1918 (the Electoral Act). In making a proposed redistribution, the Redistribution Committee and the augmented Electoral Commission are bound by the Electoral Act to ensure that the number of electors in each proposed electoral division does not deviate by more than 10 per cent above or below the current enrolment quota. The current enrolment quota for Western Australia was determined by the Electoral Commissioner to be 94 026 as at 1 December 2014.

Projected enrolment at 8 February 2017 is supplied because, as far as practicable, the Redistribution Committee and the augmented Electoral Commission are required to ensure that the number of electors enrolled in each division at 8 February 2017 (the projection time) will not deviate by more than 3.5 per cent above or below the projected enrolment quota. The projected enrolment quota is 99 686.

A growth (%) figure is also provided. This is the estimated growth rate for the period December 2014 to February 2017. The growth rate shown for each SA1 is calculated by subtracting the actual enrolment from the projected enrolment, then dividing by the actual enrolment. The result is expressed as a percentage.

The following information is provided for each division in Western Australia:

  • the name of each SA2 in the division,
  • the identifier number of each SA1 or part SA1 in the division,
  • the two sets of enrolment figures and the growth rates applicable to each SA1, part SA1 and SA2 and for each existing electoral division, and
  • total enrolment for the division.

How are projected enrolment figures calculated?

Following a recommendation by the Joint Standing Committee on Electoral Matters (JSCEM) that the AEC and the Australian Bureau of Statistics (ABS) work together on enrolment projections, the ABS has supplied enrolment projections to the AEC using AEC enrolment data as the base. The ABS has used a cohort-component method to project the enrolment of each SA1. The methodology is detailed in the appendices included with this document.

Divisional Returning Officers (DROs) were asked to examine the ABS projections in the light of their local knowledge and experience, and to substitute their own projections where appropriate. The Australian Electoral Officer and State Manager for Western Australia also reviewed the projections to ensure a consistent approach.

Why are enrolment figures supplied at the SA1 level?

Enrolment figures are provided at the SA1 level, as this level is the smallest commonly used geographic building block. The SA1 figures are aggregated to show the totals for SA2s, which are comprised of a number of SA1s. Being somewhat larger than SA1s, SA2s may be more manageable for those who are interested in less detailed analysis.

The figures shown are broken down according to electoral division. Where a SA1 or SA2 crosses divisional boundaries, the SA1 or SA2 concerned will be listed in each division in which electors are enrolled. Only those electors resident in that division are included in the figures for such SA1s or SA2s.

How is the enrolment data provided?

Data is provided in the following CSV files:

Each file contains:

  • SA2 name
  • SA1 number
  • enrolment as at 1 December 2014
  • projected enrolment as at 8 February 2017.

Spatial data

The existing federal boundaries for Western Australia are provided in a spatial format.

You will need GIS software to view and manipulate spatial data; however TAB files have been provided for those who do not have GIS software. To view the TAB files, you can download MapInfo ProViewer software which is a free MapInfo viewer from Pitney Bowes.

Access to a computer with the software program, Electoral Boundary Mapping System (EBMS), which runs within the commercial software program MapInfo, will be made available for interested persons at the office of the Redistribution Committee for Western Australia in Perth.

Bookings will be required and can be made by phoning the WA Redistributions Secretariat on 08 6363 8043 during business hours (9am to 5pm). Some knowledge of the systems will be assumed and only a brief introduction can be offered. Access to this system will be available during the periods allowed for suggestions, comments on suggestions, objections and comments on objections.

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