Identify Friend or Foe
An organization's support for a bill is calculated as the average position for all people signing in for committee hearings on that bill from that organization, with 'Pro' counting as 1, 'Con' as -1 and 'Other' as 0. (All positions are included, regardless of whether they actually testify.) Member support for a bill is calculated as the average roll call floor vote, counting 'Yea' as 1, 'Nay' as -1, and 'Absent or Excused' as 0.
A correlation coefficient is then calculated between the bill sequence for the organization and each member of the legislature. Members who always take the organization's position will have 100% correlation and those who always take the opposing position will have -100% correlation.
More information is available at the sites below: