# Debian pairwise voting (fwd)

DEMOREP1 at aol.com DEMOREP1 at aol.com
Sun Feb 6 07:57:24 PST 2000

```Mr. Ossipoff wrote--

40: A (the A voters truncate)
25: B (2nd choices of B voters aren't listed, since they're likely
to be divided both ways, and we don't know which side would
get more from them)
35: CB

***

The A truncation makes a circular tie, though B is the Condorcet
winner. In the resulting IRV count, B gets eliminated, and A
wins.

The reason why the A voters are in a position to make a circular
tie is because A beats B pairwise. Otherwise truncation or
order reversal would merely make C win. Since A beats B pairwise,
that means that A beats B in IRV after B is eliminated.

So pairwise, with circular ties solved by IRV is perfectly set
up to reward truncation & order-reversal, and to force a majority
to use defensive strategy to get its way.

The majority preferring B to A can only prevail if, when
A voters truncate, the C voters insincerely move B up to
1st place, with C. If A voters order-reverse, the only way
to keep A from winning is if the C voters actually vote B
over C, moving B to 1st place, and moving C down to 2nd place.

Of course the B voters could also thwart the truncation or
order-reversal, if they insincerely vote C over A. But, for
one thing, that requires that they know froml which side the
truncation or order-reversal will come.

I've just described the general pairwise defensive strategy.
With most pairwise methods, that's all that's available. With
Condorcet's method truncation isn't a problem, and order-reversal
can be thwarted by mere defensive truncation by B voters.
---
D- Minor question- what/where was the original posting regarding the Debian
rules ???

There should be a YES/NO vote on each choice to get a majority acceptable YES
choice (to greatly reduce plurality related strategy/order
reversal/truncation games).

Head to head math would happen only if 2 or more choices each get YES
majorities of all of the voters (with minority voters choosing the lesser of
the 2 or more perceived majority evils using rank order number votes).

Example-