Want to establish a better partisanship score for Congress? Here's my methodology: get footage from a wide-angle camera mounted on the ceiling of the House Chamber. At every applause line in the State of the Union, compute an "agreement with the President" score based on: Does X clap? Does X stand? Sum the scores for each Senator and Representative.
$20 says it correlates at .95 or better with DW-NOMINATE Dimension One. And you don't even have to do any icky scaling; just enslave a few grad students to do the math... :-)