Proportional and Semi-proportional Voting Systems

"Victory Thresholds" of Representation:
Candidate-Based Proportional and Semi-Proportional Systems

A variety of different formulas are used to translate votes into seats in proportional and semi-proportional voting 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 candidates can win a seats with a lower share of votes this this threshold, but can't be guaranteed such a win unless they win this share.

Number of seats in district

1 (winner-take-all)

2

3

4

5

6

7

8

9

Threshold to win one seat

One vote more than:

50.0%

33.3%

25.0%

20.0%

16.67%

14.3%

12.5%

11.1%

10.0%

9.1%

"Victory Threshold" of Representation =

This factsheet is part of the CVD Factbook Series, a compilation of one-page factsheets covering voting systems and voting system reforms.