[EM] virtual round robin slideshow

James Green-Armytage jarmyta at antioch-college.edu
Fri Nov 12 20:09:11 PST 2004


	Interesting approach, Brian. I like the "brand" name VRR, it's kind of
neat if you want to go with the whole acronym thing.
	Have you tried this out on anyone yet? What was their response?
	What I've been doing lately to explain the pairwise method is to have
people rank 5 movies against each other, and then do pairwise comparisons
one at a time, asking people to raise their hands if they liked movie X
more than movie Y, and then a show of hands for Y>X. Doing pairwise
comparisons this way, sort of questing for a Condorcet winner, that is,
following a single movie until another one defeats it. That seems to work
pretty well.
	I agree with Adam that it ends too abruptly. You go into a lot of detail
about how the matrix is constructed, but then you really rush through the
part where you talk about the implications of a given matrix. So, yes, you
would want to develop that part.
	Myself, I'm not sure if it's best to start with matrixes when talking to
beginners. I usually just break it into separate lines, like if you have
four candidates Alice, Bob, Carl, and Dave, I just do something like this:

Alice vs. Bob:	Alice beats Bob, 16-15
Alice vs. Carl:	Carl beats Alice, 17-14
Alice vs. Dave:	Alice beats Dave, 16-15
Bob vs. Carl:	Bob beats Carl, 17-14
Bob vs. Dave:	Bob beats Dave, 20-11
Carl vs. Dave:	Carl beats Dave, 16-15
	So, Alice beats Bob, Bob beats Carl, Carl beats Alice, and everyone beats
Dave.

	Of course, it's much less compact than a matrix, but I think far, far
easier for a normal person to understand. I tend to think that the matrix
shouldn't be introduced until later, as a way of abbreviating the results.
	I think that the above notation works particularly well when there is a
Condorcet winner, because you only need to look at their comparisons. When
there is a cycle, I like to illustrate it using arrow diagrams like these:
http://fc.antioch.edu/~jarmyta@antioch-college.edu/voting_methods/diagrams/image002.gif
http://fc.antioch.edu/~jarmyta@antioch-college.edu/voting_methods/diagrams/image017.gif

	Anyway, that's just my approach... it's just whatever gets through to
people, though; there's no single necessary way to do it. I'm wondering,
what kind of charts do actual round robins use? Do you know?

my best,
James




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