# Re: Norman Petry and I (Ossipoff) recommended CSSD, but Schwartz Woodall is a better voting system for Debian

```Michael Ossipoff writes ("Norman Petry and I (Ossipoff) recommended CSSD, but Schwartz Woodall is a better voting system for Debian"):
> Example 1:
>
> Sincere preferences:
>
> 99: A>B>>C
> 2: B>A>>C
> 100: C>>(A=B)
>
> The A voters rank sincerely, and the B voters defect:
>
> 99: A>B
> 2: B
> 3: C

In Debian's system, this will result in A winning.

A vs B:
99x "A>B"  count as preferring A to B
2x "B"    count as preferring B to A
3x "C"    count as preferring neither A to B, nor B to A
So A defeats B.

A vs C:
99x "A>B"  count as preferring A to C
2x "B"    count as preferring neither A to C, nor C to A
3x "C"    count as preferring C to A
So A defeats C.

The Schwartz set contains only A.

> 2 defecting B voters have stolen the election from 99 co-operative A voters.

So you have misunderstood Debian's voting system.  See particular
Constitution A.6(1).

> ----------------------------
>
> Here's another example in which the 3 factions are nearly equal in size:
>
> Sincere preferences:
>
> 33: A>B>>C
> 32: B>A>>C
> 34: C>>(A=B)
>
> Actual votes, when A voters co-operate and B voters defect:
>
> 33: A>B
> 32: B
> 34: C

A vs B:
33x "A>B"  count as A>B
32x "B"    count as B>A
34x "C"    count neither way
A defeats B by 33:32

A vs C:
33x "A>B"  count as A>C
32x "B"    count neither way
34x "C"    count as C>A
C defeats A by 34:33

B vs C:
33x "A>B"  count as B>C
32x "B"    count as B>C
34x "C"    count as C>B
B defeats C by 65:34

The Schwarz set contains A,B,C.  We drop the weakest defeat, which is
A>B by one vote because 33<34.

> Again, though A is CW, B wins by defection.

However this seems quite a risky strategy by the B voters.  The
situation seems contrived and unlikely to arise in practice.

Ian.

```