Maine 2018 Democratic Gubernatorial Primary

The Maine 2018 Democratic Gubernatorial Primary took place on 2018-06-12. Janet T. Mills won after four runoff rounds, and was also the Condorcet winner.

Runoff Rounds

This diagram shows the votes of each remaining candidate at each round, as well as the breakdown of votes transferred when each candidate was eliminated.

Janet T. Mills Adam Roland Cote Elizabeth A. Sweet Mark W. Eves Mark N. Dion Diane Marie Russell Donna J. Dion Write-in Exhausted Ballot Janet T. Mills Adam Roland Cote Exhausted BallotRound 1Round 2Round 3Round 4

Pairwise Preferences

For every pair of candidates, this table shows what fraction of voters preferred one to the other. A preference means that either a voter ranks a candidate ahead of the other, or ranks a candidate but does not list the other. Ballots which list neither candidate are not counted towards the percent counts.

Less PreferredMore PreferredJanet T. MillsAdam Roland CoteElizabeth A. SweetMark W. EvesMark N. DionDiane Marie RussellDonna J. DionWrite-inJanet T. MillsAdam Roland CoteElizabeth A. SweetMark W. EvesMark N. DionDiane Marie RussellDonna J. DionWrite-in54.1%61.3%60.4%78.7%83.9%87.4%98.7%45.9%55.2%56.3%75.3%79.9%84.1%98.7%38.7%44.8%49.6%71.4%81.0%85.2%98.7%39.6%43.7%50.4%71.2%79.9%81.7%98.6%21.3%24.7%28.6%28.8%61.9%66.7%97.9%16.1%20.1%19.0%20.1%38.1%55.9%97.4%12.6%15.9%14.8%18.3%33.3%44.1%97.0%1.3%1.3%1.3%1.4%2.1%2.6%3.0%

First Alternate

For every pair of candidates, this table shows the fraction of voters who ranked one candidate first ranked the other candidate second.

Second ChoiceFirst ChoiceJanet T. MillsAdam Roland CoteElizabeth A. SweetMark W. EvesMark N. DionDiane Marie RussellDonna J. DionWrite-inJanet T. MillsAdam Roland CoteElizabeth A. SweetMark W. EvesMark N. DionDiane Marie RussellDonna J. DionWrite-inExhausted Ballot23.8%23.2%22.7%8.7%3.5%2.4%0.1%15.7%29.6%16.9%24.1%9.1%2.0%4.1%0.1%14.0%26.2%17.6%30.6%4.8%10.2%2.9%0.1%7.6%27.2%23.0%33.2%5.5%2.9%1.5%0.1%6.8%24.1%19.8%12.3%15.9%6.4%5.8%0.1%15.7%15.4%10.7%36.7%13.2%10.2%5.8%0.1%7.9%18.4%18.7%11.5%8.3%14.8%7.9%0.4%19.9%9.4%9.2%7.2%4.1%3.9%1.5%2.5%62.2%

Final-round vote by First vote

For each candidate who was eliminated before the final round, this table shows which final-round candidate the eliminated candidate's first-round ballots went to.

Final Round ChoiceFirst ChoiceElizabeth A. SweetMark W. EvesMark N. DionDiane Marie RussellDonna J. DionWrite-inJanet T. MillsAdam Roland CoteExhausted Ballot47.1%36.4%16.5%44.0%41.1%14.9%40.1%36.8%23.1%44.9%33.2%21.9%34.8%34.3%30.8%16.2%16.2%67.6%

Honest Approval Set

Another voting system is Approval Voting, which involves indicating one or more candidates you approve of without ranking them. The candidate with the most voters who approve of them wins. It is impossible to know how voters would vote on an approval ballot based on their ranked ballot, but two reasonable assumptions we can narrow down the set of possibe approval ballots. With these possible approval ballots, we can determine which candidates would have had a chance of winning under an approval voting system.

The assumptions we make are:

  • Every voter who ranked at least one candidate would have voted for at least one candidate in an approval vote.
  • Every voter’s approval votes would be consistent with their ranked ballot, that is, they would not vote for a candidate unless they also voted for every candidate who appeared above that candidate on their ranked ballot.

The table below shows the maximum vote margin each candidate could have received (over the next best candidate) in an approval system, subject to these assumptions.

CandidateMost Favorable Scenario
Janet T. MillsWins 99,942 to 47,935
Adam Roland CoteWins 92,854 to 55,663
Elizabeth A. SweetWins 88,291 to 60,155
Mark W. EvesWins 87,108 to 58,694
Mark N. DionWins 64,105 to 63,832
Diane Marie RussellLoses 64,155 to 55,181
Donna J. DionLoses 64,584 to 51,172
Write-inLoses 43,084 to 3,407

Meta

NameMaine 2018 Democratic Gubernatorial Primary
Date2018-06-12
Total Ballots132,250
Input Formatus_me
Tabulation Methodeager_irv
Normalized Ballot Dataus/me/2018/06/gov-primary/us_me_2018_06_gov-primary.normalized.csv.gz

Raw Input Data

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us/me/2018/06/gov-primary/govd-2.xlsx1ba44a180dcbd5828c0ae23e6740d4c20f74953e
us/me/2018/06/gov-primary/govd-3.xlsxcca35ca455a1020ede3b52473ed9ded924d1d1a9
us/me/2018/06/gov-primary/govd-4.xlsx76f1ac0501f4ec24557a389d7947da2ddedf41e2
us/me/2018/06/gov-primary/govd-5.xlsxd3433bb08666bb7bcfb27cd706b1ecfebf048dfa
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