| − | The '''Cook Index''' measures how [[Democratic Party|Democratic]] or Republican Party|Republican]] a district or [[List of 50 states|state]] is with respect to the national average over the past two [[POTUS|presidential elections]]. For example, a congressional district score of D+1 means that Democratic presidential candidates obtained an average of 1 percentage point more than the national average in that congressional district over the last two presidential elections. | + | The '''Cook Index''' measures how [[Democratic Party|Democratic]] or [[Republican Party|Republican]] a district or [[List of 50 states|state]] is with respect to the national average over the past two [[POTUS|presidential elections]]. For example, a congressional district score of D+1 means that Democratic presidential candidates obtained an average of 1 percentage point more than the national average in that congressional district over the last two presidential elections. |