How e dey work, well well
With n options, first place carry nβ1 points, second nβ2, and so on down to 0 for last. Dem add each option points.
Di Dowdall variant (Nauru dey use am) give 1, 1/2, 1/3β¦: e dey weight top places heavy pass. Di scale dey change di result β no be small implementation detail.
Placet dey use di classic nβ1, nβ2, β¦ 0 scale, wey make di gaps easy to read: one point na exactly one rank wey you gain for one ballot.
Example wey get figures
Three options, five ranked ballots. First place na 2 points, second 1, third 0.
| Ballots | 1st | 2nd | 3rd |
|---|---|---|---|
| 2 voters | Lyon | Bordeaux | Lille |
| 2 voters | Lille | Bordeaux | Lyon |
| 1 voter | Bordeaux | Lyon | Lille |
- Lyon: 2Γ2 + 1Γ1 = 5 points.
- Lille: 2Γ2 = 4 points.
- Bordeaux: 2Γ1 + 2Γ1 + 1Γ2 = 6 points.
Bordeaux win even though almost nobody put am first β na everybody second choice. Na exactly wetin Borda wan capture, and na exactly wetin im critics dey use against am.
Where e come from
Jean-Charles de Borda β sailor, mathematician and physicist β carry im paper on election by ballot go di Royal Academy of Sciences for 1770; dem publish am for 1781. Im point simple: normal voting fit elect candidate wey di majority no want.
Di idea old pass dat. Di Majorcan philosopher Ramon Llull describe pairwise comparison and ranking since end of di 13th century β na for 2001 dem come find di manuscripts. Nicholas of Cusa propose points method for 1433 to elect di Holy Roman Emperor.
Di Academy of Sciences use Borda method to elect members, until Napoleon, wey join for 1797, make dem drop am. Borda don already answer di manipulation talk before: im scheme, e talk, na for honest people only.
Where dem dey use am
- Parliament elections for Nauru and minority seats for Slovenia.
- Sports and culture awards: Ballon d'Or, MVP trophies, book prizes.
- To set agenda or collective priority, when you must compare all di options.
- Team decisions where you want di option wey dey divide people less.
Limits and wahala
- E reward broad agreement
- E take di whole ranking into account
- E simple to calculate
- E dey sensitive to "clone" candidates
- E open to tactical ranking
- E fit push aside favourite wey divide people
Questions wey people dey ask
Borda or Condorcet?
Borda dey measure average satisfaction and e dey always give result; Condorcet dey look for di champion of all duels, but e fit find none. Borda strong pass for practice, Condorcet strict pass for theory.
I must rank all di options?
Ideally yes: incomplete ballot dey spoil di relative points. Na di real cost of di method, and na why e dey tire people once options pass seven or eight.
Why last place na zero?
So dat na only di GAPS between ranks go count. If you add same number to every rank, di final order no go change; to start from zero just make am easy to read.