On 04/05/2013 01:50 AM, Forest Simmons wrote:
Kris,
Optimal MJ strategy is still approval strategy. You can instruct the
voters to make absolute choices, but you cannot enforce it. Their
willingness to abide by the instructions is purely psychological. The
same psychology will work, only better for Consensus Threshold Approval.
True, but B&L have some evidence that
- the grade ballot in conjunction with MJ produces that kind of
psychological willingness,
- an Approval ballot as usually phrased induces relative comparisons
instead,
- and the text (instructions) on a ballot can reduce or increase the
degree to which the voters make relative choices.
They also suggest that the grade format itself is important in creating
a setting where the voters have a psychological willingness to make
absolute choices. They use two arguments:
First, that grades have common meaning as categories in themselves
whereas a finely graduated scale induces a numerical (comparative) kind
of thinking;
and second, that MJ, not caring about the distances between the grades,
supports a view where grades are seen as categories in themselves, and
thus where it's natural to do absolute comparisons rather than relative
ones.
What I mean by "not caring about the distances between the grades" may
need a little more explanation. Say the voters have a common concept of
the grades as being points from -10 to 10 on some utility scale. Then
say there's an MJ election and X wins. After the election, perturb the
grades-utility mapping according to some monotone transformation and run
the MJ election with the same underlying utilities again. X will still win.
Unless I'm mistaken, I think that'll be true of any system that only
considers the order of the ratings (as median does, picking the
middlemost) rather than making use of the ratings' numerical value. And
since it only makes use of the order of the ratings (the grades, in this
case), it doesn't need to assign an explicit value to any of them.
They're just letters and it only needs to know that an A is better than
a B and so on down.
Is that true of CTA as well?
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