A couple of Dartmouth researchers counting words and themes from published speeches of the presidential candidates to bring some quantification to political analysis. Here’s their paper (in PDF) and here’s the university’s press release.

This is the conclusion I thought was most interesting. It says Edwards and Romney were much more critical of their opponents than the other major candidates. I was surprised about Edwards, who I thought had been Mr. High Road:

Mentions of Opponents in Campaign Speeches During 1/1/2006 to 1/14/2008

Candidate Negative Mentions Per 10,000 Words

Hillary Clinton 1.376
Barack Obama 1.803
John Edwards 6.568

Fred Thompson 2.283
John McCain 3.018
Mitt Romney 8.517