The changes to the Commonwealth Electoral Act are to:

• set aside that part of the Electoral Commissioner’s determination of 3 July 2020 which applied to the Northern Territory. As a result, the divisions of Lingiari and Solomon will be contested at the next federal election on the same boundaries that were used at the 2019 federal election.
• alter the way the number of members of the House of Representatives will be calculated for the ACT and NT from the next determination.
  • this will use the harmonic mean when the number of members is between 1 and 3. Whether to round up or down will occur at a remainder other than at .5. The thresholds to round up or down are at 1.3333 and 2.4.
  • the provisions which allow for an alteration of the ACT or NT population by the inclusion of twice the standard error of the net undercount at the most recent census have been removed.
• retain the minimum number of members of the House of Representatives for the ACT and NT at one.

The harmonic mean is calculated using the formula:

(2 x Minimum number of members x Minimum number plus 1)
÷
(Minimum number of members + Minimum number plus 1)

Where:

• Minimum of members is the minimum of members worked out for the Territory when dividing the ascertained population by the population quota.
• Minimum number plus 1 is the result of adding 1 to the minimum of members worked out for the Territory when dividing the ascertained population by the population quota.

The harmonic mean will be used only in the following circumstances:

• when working out the number of members of the House of Representatives a Territory is entitled to – that is, it doesn’t apply to working out the number of members for any of the States
• when the result of dividing a Territory’s ascertained population by the population quota is 1 or more and less than 3 – that is, it doesn’t apply when the result of this division is 0.68 or 3.1 or 4.7.

Information about calculating the number of members of the House of Representatives is available on the AEC website.

Formal commencement is on proclamation, which must occur within two months of receiving Royal Assent.

Practically speaking, the new way to calculate the number of members in the ACT and NT will not be used until after the next federal election, when the next entitlement determination is made. Under the Commonwealth Electoral Act 1918 (the Electoral Act), the Electoral Commissioner is required to use the latest official published statistics of the Commonwealth to ascertain the Australian population on the day after the one-year anniversary of the first meeting of the House of Representatives. The next entitlement determination will occur after the following has happened:

• a general election has been held
• the House of Representatives in the 47th Parliament has met for the first time
• the House of Representatives has continued to meet for 12 months following the first meeting day.

You can check your electorate at any time by using Check my enrolment or Find my electorate. Following formal commencement, these will be updated to reflect the divisions of Lingiari and Solomon.