[EM] Confirmed!: Condorcet efficiency of IRV > 2-stage runoff

[Rob LeGrand]

Oh hell . . . I mistyped the sizes of some of the voting blocs.  Sorry
about that.

Sincere preferences:

45:Reagan>Anderson>Carter
35:Carter>Anderson>Reagan
20:Anderson>Carter>Reagan

Plurality equilibrium:

45:Reagan
35:Carter
20:Carter   <--- insincere

IRV equilibrium:

45:Anderson>Reagan>Carter   <--- insincere
35:Carter>Anderson>Reagan
20:Anderson>Carter>Reagan

Note that there are two other plurality equilibria.  In fact, there's a
plurality equilibrium for each sincere pairwise majority in an
election, so there's always at least one that elects the Condorcet
winner.  I believe the IRV equilibrium above is unique, so all of the
plurality and IRV equilibria for this electorate entail insincerity.

=====
Rob LeGrand
robl at aggies.org
http://www.aggies.org/robl/
for Texas State Representative, District 50

__________________________________________________
Do you Yahoo!?
New DSL Internet Access from SBC & Yahoo!
http://sbc.yahoo.com

----
For more information about this list (subscribe, unsubscribe, FAQ, etc), 
please see http://www.eskimo.com/~robla/em