Condorcet Completion — Ranked-Pairs

As said, the particular Condorcet method proposed to replace FPTP is “Ranked-Pairs”:

“Ranked pairs (RP) or the Tideman method is a voting system developed in 1987 by Nicolaus Tideman that selects a single winner using votes that express preferences.

“RP can also be used to create a sorted list of winners.

“If there is a candidate who is preferred over the other candidates, when compared in turn with each of the others, RP guarantees that candidate will win.

“Because of this property, RP is, by definition, a Condorcet method….”
Ranked Pairs, Wikipedia

Condorcet Completion

As previously noted for Condorcet methods in general, it’s a “round-robin” competition — Every candidate competes one-on-one against each other candidate to determine the outcome.

Each voter casts a single ballot, in a single election round, indicating his or her relative preferences among the candidates.

Ballots are NOT weighted, and there is NO “process of elimination” of candidates — all voter preferences from all ballots are evaluated holistically.

Ranked-Pairs is a Condorcet “completion”; it “completes” the fundamental Condorcet concept by cleanly and simply resolving preference-cycle situations, should any arise when considering the ballots all together.

Ranked-Pairs Applications

In addition, while the immediate focus is to replace single-member FPTP election systems, there are meaningful applications for IRV (or AV) systems, as well as multiple- and proportional-representation systems:

  1. For some multiple-representation (MR) systems, such as Multiple-Member Plurality (MMP), for example, or the Single Transferable Vote (STV), a straightforward replacement by Ranked-Pairs is available.

    Ranked Pairs determines an ordered list of candidates, according to voter-preferences, from which the n most-preferred candidates can be selected.

  2. Some proportional-representation (PR) systems, such as Mixed-Member Proportional Representation (MMPR), use first-past-the-post (FPTP) to elect single members in constituencies (then allocates additional seats on a party-list basis to achieve proportionality).

    By-elections to fill vacancies in multi-member districts, or for PR systems, are often done by FPTP, as well.

    These FPTP elections constitute serious flaws in these systems. These flaws can be easily corrected, however, by replacing the FPTP elements with Condorcet voting.

Next: The Problem at Hand

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