part 6, 1st Choice Criterion

Mike Ositoff ntk at
Wed Nov 4 18:20:21 PST 1998

There's also a class of methods called the "pairwise-count"
or "pairwise" methods. They start out:

Voters rank as many candidates as they wish. A beats B if
more voters rank A over B than vice-versa. If 1 candidate beats
each of the others, he wins.

Sometimes there isn't such a candidate. When there is, he's
a CW. When there isn't, however, that doesn't necessarily
mean there isn't a CW. Maybe there is one, but he's losing
his win due to truncation or order-reversal.

Truncation means voting a short ranking rather than ranking

Order-reversal means strategic reversal of a preference ordering.

In general, pairwise methods fail weak & strong versions
of the 1st Choice Criterion. Truncation is all it takes
to makek them fail the strong version. Order reversal makes
them fail the weak version.


More information about the Election-Methods mailing list