[EM] IRV's Top Preferences Considered First Feature

[Forest Simmons]

I'm not advocating approval runoff, only using it as a method that can be
easily compared with IRV, because IRV can be thought as a special case of
approval runoff where the ballots are constrained, just as plurality can
be thought of as a special case of approval in which the voters are
constrained to mark only one candidate, otherwise resulting in a spoiled
ballot.

True, Approval doesn't allow you to rank the candidates, but that would be
impossible with a plurality style ballot, whereas Approval is possible is
with that style ballot.

There are many versions of approval runoff, some of which do require
repeated trips to the polls, but the one that I am suggesting is an
instant runoff like IRV, summable in 2^N pieces of data, and using the
same kind of ballot as IRV except the ballot cannot be spoiled because the
voter is unconstrained.

Removing the constraint of one mark per column turns the IRV ballot into a
(dyadic) CR ballot from which approval runoff can be simulated as well as
IRV simulates ordinary plurality runoff.

In IRV one row of the ballot looks like this:

Jane Doe   (1st)    (2nd)   (3rd)    (4th)    (5th),  etc.

The voter marks one column to indicate the rank of Jane Doe, or else
truncates by marking no column.

In the dyadic CR ballot each column has a place value:

Jane Doe   (2^0)     (2^1)    (2^2)    (2^3),  etc.

The voter can mark any number of columns.  The sum of the powers of two is
the CR score for Jane Doe.

Thus an IRV ballot allowing five candidates to be ranked can be used as a
dyadic CR ballot with a resolution of 2^5=32 since the corresponding sums
of powers of two (from 2^0 to 2^4) range from zero to 1+2+...+16=31.

Approval runoff can be simulated by using the convention that a ballot
approves a candidate if that candidate's CR score is above the mean score
of the candidates that remain on the ballot.\

The word "mean" can be replaced with "median" or  "midrange" in the above
explanation to get different versions of approval runoff.

The number of candidates eliminated at each stage can be made to depend on
how many candidates get above mean approval, as an example of other
possible variations.

Forest

On Fri, 13 Jun 2003, Dave Ketchum wrote:

>
> I am not sure exactly what "Approval runoff" is, except here it seems to
> involve getting voter involvement at each stage, after previous stage
> votes have been counted.  I see this as unacceptable for public elections,
> especially for such as mayor or governor, unless it offers some TREMENDOUS
> advantage.  Here the first stage would be voted by each voter during
> election day.  The next stage would have to be at some later date.