consensual decision making by peter emerson, the de borda institute
TRANSCRIPT
Peter Emerson
The de Borda Institute
August 8 2013, Wood Quay Venue, Dublin @ogpconsultirl #ogpIRL
SOCIAL CHOICESand
SOCIAL RANKINGS
The de Borda Institute
www.deborda.org
DECISION-MAKING
Questions
MEDIATION open, multi-optional
POLITICS closed, majority votes
MAJORITARIANISM
The (simple or weighted) two-option majority vote is the most inaccurate measure of collective opinion ever invented
CLOSED
QUESTIONS
SEMI-OPEN
QUESTIONS
OPEN
QUESTIONS
↑All
Prefs
DECISION-MAKING Borda
BC / MBC
C AV = alternative vote
BC = Borda Count
IRV = instant run-off
MBC = modified Borda count
STV = single transferable vote
Condorcet
(Copeland)
OSome
Approval
voting
U prefs Serial voting
Sweden*
AV = IRV =
STV
N 1st
prefs
only
Weighted majority
EU, SA, UN
Consociational
NI, Belgium
2-round voting
Norway**
T Simple majority
Ireland, UK, etc.
Twin Majority
Switzerland
Plurality
New Zealand
* a series of
majority
votes
** a first-
round
plurality
and then a
majority
vote
1 of 2
options
1 of some
options
1 or some of
some options
1or some or all
of all options
1st preference only Preferential
BINARY MULTI-OPTIONAL
VOTERS’ CHOICE → →
PARTIAL VOTING IN A 5-OPTION MBC
• He who votes for 1 option gives his favourite 1 pt.
PARTIAL VOTING IN A 5-OPTION MBC
• He who votes for 1 option gives his favourite 1 pt.
• She who votes for 2 options gives her favourite 2 pts (and her 2nd choice 1 pt).
PARTIAL VOTING IN A 5-OPTION MBC
• He who votes for 1 option gives his favourite 1 pt.
• She who votes for 2 options gives her favourite 2 pts (and her 2nd choice 1 pt).
• He who votes for 3 options gives his favourite 3 pts, (his 2nd choice 2 pts and his 3rd choice 1 pt).
PARTIAL VOTING IN A 5-OPTION MBC
If you vote for: Number of options
1 2 3 4 5
your 1ST pref gets: 1pt 2pts 3pts 4pts 5pts
your 2ND pref gets: 1pt 2pts 3pts 4pts
your 3RD pref gets: 1pt 2pts 3pts
your 4TH pref gets: 1pt 2pts
your 5TH pref gets: 1pt
BORDA COUNT (BC)
A full vote = n, n-1 … 2, 1
MODIFIED BORDA COUNT (MBC)
A full vote = n, n-1 … 2, 1
A partial vote = m, m-1 … 2, 1
CLOSED
QUESTIONS
SEMI-OPEN
QUESTIONS
OPEN
QUESTIONS
↑All
Prefs
DECISION-MAKING Borda
BC / MBC
C AV = alternative vote
BC = Borda Count
IRV = instant run-off
MBC = modified Borda count
STV = single transferable vote
Condorcet
(Copeland)
OSome
Approval
voting
U prefs Serial voting
Sweden*
AV = IRV =
STV
N 1st
prefs
only
Weighted majority
SA
Consociational
NI, Belgium
2-round voting
Norway**
T Simple majority
UK
Twin Majority
Switzerland
Plurality
New Zealand
* a series of
majority
votes
** a first-
round
plurality
and then a
majority
vote
1 of 2
options
1 of some
options
1 or some of
some options
1or some or all
of all options
1st preference only Preferential
BINARY MULTI-OPTIONAL
VOTERS’ CHOICE → →
OPEN →
THRESHOLD THRESHOLD THRESHOLD THRESHOLD
HIGH LOW HIGH LOW HIGH LOW HIGH LOW
↑
C
O
U
N
T
All
prefs
E L E C T O R A L S Y S T E M S QBS + top-up
AMS = additional member system
AV = (STV) = alternative vote FPP = first-past-the-post
MBC = modified Borda count MMP = multi-member proportional
QBS
BC/MBC
Condorcet
lots
some
prefs
few
QBS =quota Borda system
S(N)TV = single (non-) transferable vote
PR-List
Swiss
PR-STV
Ireland
N Ireland
Approval Voting
AV
Australia
PR-List
Belgium
2-round
France
Bosnia ’90
Mixed FPP + PR
Croatia ’92-’95 MMP – Germany, NZ
1st
prefs
FPP
UK
Kenya
PR-list
closed
Israel, Iraq
Bosnia ’96
Kosovo*
AMS
FPP
LebanonSNTV
Afghan-
istan
PR-list
Holland
Bosnia ’00
* with set-
aside.
1 party only 1 candidate
of 1 party
1 or some candidates of
1 or some parties
1, some or all
candidates of any or all
parties
V O T E R S ' C H O I C E →