Victory Thresholds of Representation
A variety of different formulas are used to translate votes into seats
in full representation systems. For
candidate-based systems – those systems that can be used in
non-partisan races without parties – the threshold typically is
established by the workings of the system rather than an electoral law.
For these systems – cumulative voting and the one-vote version of
limited voting -- and for the most common form of choice voting (with
the "Droop" threshold), the thresholds to be guaranteed an opportunity to earn a seat are listed in the chart below. Note that
in some circumstances candidates can win seats with a lower share of votes than this
threshold, but can't be guaranteed such a win unless they win this
share.Number of Seats in District | Threshold to Win One Seat |
One vote more than: | |
1 (winner-take-all) | 50.0% |
2 | 33.3% |
3 | 25.0% |
4 | 20.0% |
5 | 16.7% |
6 | 13.3% |
7 | 12.5% |
8 | 11.1% |
9 | 10.0% |
10 | 9.1% |
These percentages are calculated using the following formula (known as the "Victory Threshold formula" or the "Droop" formula):
"Victory Threshold" =