Ideology Analysis of Members of Congress
The Govtrack ideology analysis assigns a liberal–conservative score to each Member of Congress based on his or her pattern of cosponsorship.
In a nutshell, Members of Congress who cosponsor similar sets of bills will get scores close together, while Members of Congress who sponsor different sets of bills will have scores far apart. Members of Congress with similar political views will tend to cosponsor the same set of bills, or bills by the same set of authors, and inversely Members of Congress with different political views will tend to cosponsor different bills.
You can find this analysis on the pages for current Members of Congress. The charts to the right plot the ideology score on the horizontal axis and the leadership score on the vertical axis. Look at the extremes. For instance, Sen. Jim Inhofe appears as the most extreme Republican in the Senate chart and he is widely regarded as one of the most conservative senators.
