initiative 318 (irv) election methods a presentation of issues addressed by washington state...

Initiative 318 (IRV)& Election Methods

A presentation of issues addressed by Washington State Initiative 318 and a

discussion of possible alternatives.

Monday, 11/29/2004 Nathan Herring 2

Abstract• Two big changes 318 introduces:

• Changing plurality voting to IRV voting.• Abolishing the primary election.

• What this presentation will discuss:• What is IRV?• What are alternative methods?

• and how do you judge them?• What are the implications of rolling the

primary election into the general election?

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GlossaryStrategic Voting -- When you vote contrary to

your preferences in order to get a better outcome. It is generally preferable to have systems that minimize the utility of such voting. Also called Tactical Voting.

Viable Candidates -- Candidates with a real shot at winning the election; strategy can often change depending on the number of viable candidates.

Exhausted Ballots -- In ranking systems, ballots where every candidate has been eliminated.

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Glossary, continuedClones -- Candidates that voters rank the

same relative to the rest of the candidates.Sincere Voting -- Opposite of strategic voting;

voting (all of) your true preferences.Truncated Preferences -- Not ranking or rating

every candidate.Spoiling -- Voting for third parties &

independents splits votes off of a viable (secondarily-preferred) candidate, causing them to lose.

Election Methods

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What is IRV?IRV is Instant Run-off Voting.• Instead of voting for one candidate, you

rank all the candidates.• If no candidate wins the majority, there is

a virtual run-off.• The candidate with the least first-choice votes

is stricken from the rankings on the ballots.• Some ballots may end up having a new first-

choice.• Check again for a winner, and if not keep

striking candidates until there is a winner.

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Demonstration

http://www.chrisgates.net/irv/

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Where is IRV in use?• In Australia, it’s called Alternative

Vote and is used to elect their Representatives and members of some lower Parliaments.

• In California, it’s called Ranked Choice Voting (RCV), and first used this fall.

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Alternative Methods & Types

Type 1: “Regular” ballot methods• Plurality, the status quo• Approval

Type 2: Ordinal (Ranked) ballot methods• Instant Runoff Voting (IRV)• Borda• Condorcet, or Instant Round-Robin

VotingType 3: Cardinal (Rated) ballots

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Type 1: “Regular” ballot methods

• These methods employ the ballot we use today, where there are ovals next to candidate names.

• Validation and calculation, however, may change.

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PluralityThe candidate with the most votes wins.• Voting for non-viable (e.g., third party)

candidates, can be “spoiling”.• “Lesser of two evils”• It is, however, simple.

• Easy to vote -- Choose one.• Easy to strategize -- Pick your favorite

viable candidate.

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ApprovalAlso, the candidate with the most votes wins.• You can vote for (or “approve”) as many

candidates as you want.• No spoiling -- You can vote for third parties.• If your favorite candidate is non-viable, you

still have to approve of your favorite of the viable candidates.

• Ballots remain simple, but there’s less validation a ballot reader can do.

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Type 2: Ranked ballot methods

• Requires a change to the ballot to allow voter to be able to rank candidates (1-2-3).

• Requires changes to voting machines and tabulation processes.

• Provide mechanisms to not have to have run-offs or staged elections (e.g., primary and general).

• Increases complexity of (re)counting process.

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Instant Run-off Voting• Voter can register their third-party

preference without “spoiling”.• Strategy for elections with more than two

viable candidates is not obvious.• Only one choice, the topmost, is ever

considered during a run-off round.• The top choice(s) are highly emphasized.

• Fails to meet several important criteria by which election methods are judged. (More later.)

• There’s an existing ballot initiative.

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IRV Variants• Allow equal ranking of candidates

• Mitigates some problems.• Implicit “no one” candidate, or still

count “exhausted” ballots.• Neither of these are in Initiative

318

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Borda• Mechanism

• 1st choice gets (n-1) points.• 2nd choice gets (n-2) points, etc.

• Is a regimented ranking system.• Easily victim to strategizing.

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Condorcet (Instant Round-Robin)

• Mechanism• Candidates are compared pair-wise.• If one candidate won individually over all other

candidates, then they win.• Otherwise, there is a “preference cycle”, which

must be broken.• A number of mechanisms to do this exist. (See next slide.)

• All preferences are considered (not just topmost).

• Not fully ranking the candidates might have negative consequences.• How many people are going to give a complete list?

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Condorcet: Breaking cycles

Breaking the cycle involves overruling part of the electorate, so how you do it is important:

• Plain Condorcet (PC)• Sequential Dropping (SD)• Ranked Pairs (RP), aka Maximize Affirmed

Majorities (MAM)• Schwartz Sequential Dropping (SSD)• Cloneproof SSD (CSSD)• Beatpath Winner (BW)

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Type 3: Cardinal Ratings • You rate every candidate. (e.g. 1-

10)• Approval is the simple case: (0-1).• Since rating someone < 10 and >

1 is equivalent to “watering down” your vote, the strategy is to vote as in Approval, so this is not a very interesting case.

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Judging Election Methods Good election systems meet a

number of criteria that describe how susceptible the system is to strategy, and to a lesser extent, what the logistics are in terms of calculating the results.

• Monotonicity Criterion• Condorcet Criterion• Generalized Condorcet Criterion

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Judging Election Methods, cont.

• Strategy-Free Criterion• Generalized Strategy-Free Criterion• Strong Defensive Strategy Criterion• Weak Defensive Strategy Criterion• Favorite Betrayal Criterion• Participation Criterion• Summability Criterion

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How do the methods rate?MC

CC GCC

SFC

GSFC

SDSC

WDSC

FBC

PC

SC

Plurality • • •IRVApproval • • • • •Borda • • •Condorcet • • • • • • • •

Data from http://www.electionmethods.org/evaluation.htm

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Is there a perfect method?Probably not.Arrow’s impossibility theorem

demonstrates that it is impossible to design a social choice function to choose with at least two members among three options in a way that satisfies fairness properties.

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Further JudgingHow simple is it?Even methods that produce good results

if people follow directions don’t work if people cannot or will not follow them.

Can grandma fill out a ballot successfully?

Will grandma understand it (and the need for election reform) enough to vote to enact it?

Initiative 318

“The Voters Full Choice Initiative of 2005”

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IRV for Washington State• We would adopt conventional IRV

as the mechanism for elections for all offices.• Exceptions are for county judges,

county races where the charter provides otherwise, and counties which have adopted IRV.

• Need to upgrade our voting systems (again).

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No more primary• Candidates give party affiliation.• One party can have multiple

candidates.• A party can have one official

nominee.• You vote by ranking every

candidate in one big general election.

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No Primary: Implications on IRV

• If major parties submit multiple candidates, then we can get into the more-than-two-contender area, which IRV doesn’t handle smoothly.

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Saving taxpayers money……because primaries become unnecessary.What will really happen?• Major parties submit multiple candidates

(with possibly one official candidate) -- Parties trusting in IRV to Do The Right Thing.

• Major parties submit only one candidate -- Parties taking matters into their own hands.• Coerce members to not submit themselves?

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Choosing Party NomineesNo primary; now what?• Caucuses

• Democrats doing that already.• Committee -- Nothing preventing a

party from choice by committee.• Less need for candidates for nomination

to debate topics in front of the public.• Voting the party line is voting for the

committee line.

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Summary• IRV not best method, but

• it allows third party preferences to be specified, and

• it doesn’t have strategy problems for the two-viable-candidate elections

• Good for President, but Insurance Commissioner?

• it would ready Washington for Condorcet.• Initiative 318 is still in the signature-

gathering process.

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Links• http://www.secstate.wa.gov/electio

ns/initiatives/text/i318.aspx• http://www.irvwa.org/• http://www.electionmethods.org/• http://approvalvoting.org/• http://www5.cs.cornell.edu/~andru

/civs/ -- Condorcet Internet Voting Service