Here’s an explanation of a version of STV+ known as the Ranked Ballot Remainder+ method. Please let me know your thoughts on this system!
Here’s how it works:
- 85% of MPs are elected from multi-member constituencies, each returning between 2 and 7 MPs.
- 15% of MPs are elected as regional top-up MPs.
- Each region would have approximately 19 MPs in total, including both constituency and regional representatives. This would result in a Droop quota of approximately 5% of the region-wide vote.
- Voters can choose to rank one of more parties in order of preference, and/or put an X beside the individual candidate they support from the party they ranked first. Independent candidates can run as a single-candidate list, and will have their own box on the ballot that voters can rank.
- In Canada, this system can be implemented by either merging 3-8 neighbouring ridings together, then removing one seat from each riding to serve as a regional top-up seat OR by merging neighbouring ridings to form 2-7 member ridings, while increasing the size of Parliament by only 15% to accommodate the additional regional top-up MPs.
To elect the riding MPs, here are the steps to follow:
- Calculate the Droop Quota based on the number of votes in the multi-member district and the number of seats available.
- Determine the seat quotas for each party by dividing the number of votes received by the Droop Quota.
- Award each party a number of seats equal to the whole-number portion of its seat quota, leaving a fractional remainder. For example, a party with a seat quota of 2.40 would initially receive two seats, with a remainder of 0.40.
- Assign seats to candidates within each party who have the most individual votes for the winning party/parties. This may result in some seats in the riding remaining unallocated.
- If every seat in the constituency has been allocated, the process ends. Otherwise, proceed to the next step.
- If there are remaining seats, the parties would be ordered based on their fractional remainders
- Eliminate the party with the lowest fractional remainder one by one until a party reaches or exceeds the Droop quota, thus leading to a party winning that remaining seat.
- The remaining seat is awarded to the unelected candidate with the most individual votes from the party that wins the seat under Step 7.
- Repeat Steps 6–8 for each remaining seat, stopping once all constituency seats have been allocated. Before each new round, reweight the votes of the party that won the previous seat so that its adjusted seat quota equals its fractional remainder. For example, if the party’s seat quota was 1.20 after the previous round, its adjusted quota would become 0.20 for the next round.
Regional top-up seats use the same general allocation method as constituency seats, with the following modifications:
- The Droop Quota is based on the number of votes in the entire region and based on the overall number of seats in the entire region (riding + regional top-up)
- Regional top-up seats are allocated to unelected candidates based on their party’s performance in each constituency. For each party, the candidate with the most individual votes in a constituency is eligible for a top-up seat, with only one candidate eligible per constituency. Candidates are prioritized according to the percentage of the local vote their party received, with the party’s strongest-performing constituencies prioritized first.
- If a party or independent candidate wins more constituency seats than their regional seat quota entitles them to, recalculate the regional top-up allocation. Remove all of the votes associated with the overrepresented party or independent candidate and reduce the Droop quota calculation to account for the constituency seats already won by that party or independent candidate
What happens if a party has ran too few candidates in their riding or region:
A party may receive enough votes to qualify for more seats than the number of candidates it has nominated in a constituency or region. The following rules apply.
- If a party’s seat quota exceeds the number of candidates it has nominated, its fractional remainder is calculated by subtracting the number of candidates it ran from its seat quota. For example, if a party has a seat quota of 1.73 but nominated only one candidate, its remainder would be 0.73 (1.73 − 1.00 = 0.73).
- If one or more parties have a projected seat entitlement greater than the number of candidates they nominated, their remainders are transferred first. These parties become ineligible to receive any of the remaining seats in that constituency or region, as they do not have enough candidates to fill them.