The power rankings of Congress members are compiled by Knowlegis, which operates the nonpartisan

The power rankings of Congress members are compiled by Knowlegis, which operates the nonpartisan congress.org Web site, in consultation with political academic experts and congressional staff members. The rankings consider numerous factors to determine the power of each member of Congress. The 2008 ranking is a reflection of what members of Congress accomplished the previous year. Twenty factors are grouped into four broad categories in the ranking, according to the Web site. They are: