Visually, the result reminds me of [http://xkcd.com/657/] - is this sort of diagram a recognised concept in data presentation, or a new idea?
[edit - hmm... http://en.wikipedia.org/wiki/108th_Congress]
The notion of agreement departs a little bit from the classical fraction of common votes/total votes and instead is based on a vector model of votes, using cosine similarity as a value of agreement. The agreement groups are computed by heuristically optimizing a quantity called the cohesion and which turns out is really correlated to the way people perceive social communities (the old preprint of the first paper: http://arxiv.org/pdf/1107.3231.pdf).
On my to do list: a graph that shows the loss of voters casting ballots. I needed a way to show how postal balloting disenfranchises voters (what it gives, it equally takes away).
Voting age population -> registered to vote -> voter received ballot -> returned ballot -> elections rcvd ballot -> signature verification -> challenged ballots -> overvotes/undervotes, voter intent, adjudication -> tabulated.
I'm afraid your paper's too much for my brain on a Sunday morning, but the diagrams and typesetting look really well done :)
Makes more sense now.