The Electoral Quota
The electoral quota (often called “the Droop quota” or simply “the quota”) is the formula for determining how many votes a candidate must receive in order to be elected under the proposed BC-STV system. It was invented in 1868 by an English lawyer, H.R. Droop.
The quota is:
For example, if there are 100,000 votes in a district that will elect three members, the quota is: 100,000 divided by 4 (that is, three members + 1), plus 1, which yields a quota of 25,001:
Fractions are ignored if the quota does not work out to be a whole number. For example, if the quota in an election worked out to 25,001.75 votes, it would be rounded down to 25,001.
Under BC-STV, the quota would be different in each electoral district for each election, since it depends on voter turnout and district magnitude (the number of MLAs to be elected in the district).
Why this formula?
The Droop quota is designed to produce the lowest number of votes possible while still ensuring that not too many candidates will meet or exceed it. In the example above, it is impossible for more than three candidates to receive 25,001 votes out of 100,000 votes cast.
The Quota as a Percentage of the Popular Vote
The quota as a percentage of the popular vote in an electoral district stays constant. In a three-member electoral district, it will always be 25% + 1 vote of the total votes cast.
The Quota and District Magnitude
However, the quota as a percentage of the popular votes in an electoral district varies as district magnitude changes, as follows:
|
District Magnitude |
Quota as Percentage of Popular Vote |
|
DM=1 (for by-elections) |
50.0% +1 vote |
|
DM=2 |
33.333% +1 vote |
|
DM=3 |
25.0% +1 vote |
|
DM=4 |
20.0% +1 vote |
|
DM=5 |
16.667% +1 vote |
|
DM=6 |
14.286% +1 vote |
|
DM=7 |
12.5% +1 vote |
In general, the results in electoral districts with larger district magnitudes tend to be more proportional – that is, the distribution of seats won in that district more closely match the popular vote.
Why does it work this way?
The Citizens’ Assembly on Electoral Reform considered these differences when it proposed BC-STV:
"The number of members in each district will vary from two (2) to seven (7). Given that achieving proportional electoral outcomes is a primary reason for recommending BC-STV, using larger rather than smaller numbers of members per district should always be preferred when drawing district boundaries."
Source: Citizens’ Assembly on Electoral Reform Technical Report, p. 17
The Electoral Boundaries Commission made recommendations on specific electoral districts and their district magnitudes. Most electoral districts under BC-STVwould have four or five MLAs. See Electoral Districts Information and Maps to view the district magnitude for all electoral districts.
