Distributed Multi-Voting: Difference between revisions

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If the candidates of the subset, in a certain vote, all have the same score different from 0 then, before normalization, don’t set the lowest score to 0.
 
==Tactical vote resistance==
==Criteria==
 
The original vote of the voter through point 1 of the procedure is converted, and the vote obtained is in part of the type:
{| class="wikitable" style="text-align:center"
<!-- criteria headers -->
|- style="font-size:80%; border-bottom: 2px solid #a0a0a0;"
! rowspan=1 |
! rowspan=1 style="border-left: 2px solid #a0a0a0;" | [[Majority criterion|Majority]]
! rowspan=1 | [[Majority loser criterion|Maj. loser]]
! rowspan=1 | [[Mutual majority criterion|Mutual maj.]]
! rowspan=1 | [[Condorcet criterion|Condorcet]]
! rowspan=1 | [[Condorcet loser criterion|Cond. loser]]
! rowspan=1 | [[Smith criterion|Smith]]
! rowspan=1 | [[Independence of irrelevant alternatives|IIA]]
! rowspan=1 | [[w:Independence of clones criterion|Clone proof]]
! rowspan=1 style="border-left:2px solid #a0a0a0;" | [[Monotonicity criterion|Monotone]]
! rowspan=1 | [[Consistency criterion|Consistency]]
! rowspan=1 | [[Participation criterion|Participation]]
! rowspan=1 style="border-left:2px solid #a0a0a0;" | [[Later-no-help criterion|Later-no<br>Help]]
! rowspan=1 | [[Later-no-harm criterion|Later-no<br>Harm]]
! rowspan=1 | [[Favorite betrayal criterion|Favorite<br>betrayal]]
|- style="font-size:80%;"
 
* ranking (Borda), because the points tend to be distributed linearly in the converted vote (see all cases).
<!-- Methods -->
|-
! [[Distributed_Multi-Voting|DMV]]
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
! style="background: #ffc7c7; font-weight: inherit;" | No*
|}
 
* range (Score), because by distributing the points in quite different quantities, the candidates tend to keep their score in the converted vote (see A,B,C in cases [1], [2], [3], [5] ).
{| class="wikitable" style="text-align:center; float: right; margin: 0px 20px 5px 20px;"
|- style="font-size:80%; border-bottom: 2px solid #a0a0a0;"
! rowspan=1 style="border: none; background: white;" |
! A
! B
! C
! D
|-
 
* cumulative, because the points distributed in the converted votes are however limited and fixed (700 in the case [1], 1000 in the cases [2] and [4], 1100 in the cases [3], [5], [6] based the number of candidates evaluated).
|- style="font-size:80%; font-weight: inherit; background: white;"
! style="text-align:right;" | [1] original vote
| style="font-weight: bold;" | 100
| 0
| 0
| 0
|-
 
Meets [[Honesty criterion]] under the same assumptions as the [[Distributed Voting#Tactical vote resistance|Distributed Voting]].
|- style="font-size:80%; border-bottom: 2px solid #a0a0a0; font-weight: inherit; background: white;"
! style="text-align:right;" | converted vote
| 700
| 0
| 0
| 0
|-
 
Under the same assumptions as the [[Distributed Voting#Tactical vote resistance|DV]], this system also tries to satisfy the [[Honesty criterion|Perfect Honesty criterion]], by applying a conversion of the vote which serves to drastically reduce the deviation from the honest one.
|- style="font-size:80%; font-weight: inherit; background: white;"
! style="text-align:right;" | [2] original vote
| style="font-weight: bold;" | 99
| style="font-weight: bold;" | 1
| 0
| 0
|-
 
Example
|- style="font-size:80%; border-bottom: 2px solid #a0a0a0; font-weight: inherit; background: white;"
Candidates: [A B C D E]
! style="text-align:right;" | converted vote
Honest vote: [50 30 15 5 0]
| 697
Tactical vote: [90 6 3 1 0]
| 303
Honest converted vote: [1118 820 486 176 0]
| 0
Tactical coverted vote: [1434 622 390 153 0]
| 0
Error in %: [22% 24% 20% 13% 0] Avg error = 20%
|-
633 out of 2600 is around 25%.
 
On average about 80% of the score, expressed in the tactical vote, is honest at the start of the counting, even if the voter used a tactical vote. A good representation of interests is also provided.
|- style="font-size:80%; font-weight: inherit; background: white;"
! style="text-align:right;" | [3] original vote
| style="font-weight: bold;" | 96
| style="font-weight: bold;" | 4
| style="font-weight: bold;" | 1
| 0
|-
 
'''Other properties'''
|- style="font-size:80%; border-bottom: 2px solid #a0a0a0; font-weight: inherit; background: white;"
! style="text-align:right;" | converted vote
| 686
| 292
| 122
| 0
|-
 
In cases [1] and [2] it’s noted that the addition of 1 point on B, left the score of A practically unchanged in the converted vote, but in case [2] it obtained 303 points for B (same speech observing the case [3] or even [5] ); this means that the voter has an interest in expressing his preference towards B. At the same time, the voter doesn’t even have the interest of giving his limited points to candidates he doesn’t really support (reduced [[Vote splitting]]) .
|- style="font-size:80%; font-weight: inherit; background: white;"
! style="text-align:right;" | [4] original vote
| style="font-weight: bold;" | 51
| style="font-weight: bold;" | 49
| 0
| 0
|-
 
==Systems variants (Multi-Voting method)==
|- style="font-size:80%; border-bottom: 2px solid #a0a0a0; font-weight: inherit; background: white;"
! style="text-align:right;" | converted vote
| 553
| 447
| 0
| 0
|-
 
In general, starting from a vote, all the votes are obtained for each subset of the candidates (some normalization is used), and then they are added together obtaining the converted vote. Subsequently, the count on the converted votes is applied.
|- style="font-size:80%; font-weight: inherit; background: white;"
! style="text-align:right;" | [5] original vote
| style="font-weight: bold;" | 75
| style="font-weight: bold;" | 20
| style="font-weight: bold;" | 5
| 0
|-
 
===Score Multi-Voting (SMV)===
|- style="font-size:80%; border-bottom: 2px solid #a0a0a0; font-weight: inherit; background: white;"
! style="text-align:right;" | converted vote
| 627
| 342
| 131
| 0
|-
 
The following formula is used to normalize the votes:
|- style="font-size:80%; font-weight: inherit; background: white;"
! style="text-align:right;" | [6] original vote
| style="font-weight: bold;" | 35
| style="font-weight: bold;" | 33
| style="font-weight: bold;" | 32
| 0
|-
 
[MIN, MAX] = ''[0,9]'' = range of the voting system.
|- style="font-size:80%; border-bottom: 2px solid #a0a0a0; font-weight: inherit; background: white;"
[min, max] = ''[3,6]'' = lower and higher value among the candidates of the subset, in a vote.
! style="text-align:right;" | converted vote
Cnew = new value of the candidate, in a vote.
| 490
C = old value of the candidate, in a vote.
| 381
| 229
| 0
|-
|}
 
<math>\begin{equation}
No* = the DMV can fail all the criteria but the cases in which they fail are extremely rare.
C_{new} \ =\ MIN\ +\ ( C\ -\ min) \cdot \frac{MAX\ -\ MIN}{max\ -\ min}
\end{equation}</math>
 
If max = min, then Cnew = MAX
The original vote of the voter through point 1 of the procedure is converted, and the vote obtained is in part of the type:
 
Example of normalized voting for a subset of candidates:
* ranking (Borda), because the points tend to be distributed linearly in the converted vote (see all cases).
 
Original vote: A[9] B[6] C[5] D[3] F[0] G[1] H[1]
* range (Score), because by distributing the points in quite different quantities, the candidates tend to keep their score in the converted vote (see A,B,C in cases [1], [2], [3], [5] ).
Subset {A,C,F}: A[9] C[5] F[0]
Subset {A,B,C}: A[9] B[2.25] C[0]
Subset {C,D,F}: C[9] D[5.4] F[0]
Subset {B,C,D}: B[9] C[6] D[0]
Subset {B,C,D,F}: B[9] C[7.5] D[4.5] F[0]
Subset {G,H}: G[9] H[9]
Subset...
 
By adding the converted votes, the candidate with the highest sum wins.
* cumulative, because the points distributed in the converted votes are however limited and fixed (700 in the case [1], 1000 in the cases [2] and [4], 1100 in the cases [3], [5], [6] based the number of candidates evaluated).
 
===STAR Multi-Voting (STAR-MV)===
The DMV in any case meets the [[Independence of Worst Alternatives|IWA]].
 
The converted votes are calculated, as in the Score Multi-Voting, on which the STAR count is then applied.
===Tactical vote resistance===
 
Meets Honesty criterion under the same assumptions as the [[Distributed Voting#Tactical vote resistance|Distributed Voting]].
 
This system also tries to satisfy the [[Honesty criterion|Perfect Honesty criterion]], by applying a conversion of the vote which serves to drastically reduce the deviation from the honest one.
 
Example
Candidates: [A B C D E]
Honest vote: [50 30 15 5 0]
Tactical vote: [90 6 3 1 0]
Honest converted vote: [1118 820 486 176 0] Points sum = 2600
Tactical coverted vote: [1434 622 390 153 0] Points sum = 2600
Absolute difference: [316 198 96 23 0] Points sum = 633
633 out of 2600 is around 25%.
 
On average, about 75% of the vote is honest at the start of the counting, even if the voter used a tactical vote. A good representation of interests is also provided.
 
'''Other properties'''
 
In cases [1] and [2] it’s noted that the addition of 1 point on B, left the score of A practically unchanged in the converted vote, but in case [2] it obtained 303 points for B (same speech observing the case [3] or even [5] ); this means that the voter has an interest in expressing his preference towards B. At the same time, the voter doesn’t even have the interest of giving his limited points to candidates he doesn’t really support (reduced [[Vote splitting]]) .
[[Category:Cardinal voting methods]]
[[Category:Single-winner voting methods]]
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