Fig. 3
From: Semi-supervised graph labelling reveals increasing partisanship in the United States Congress
Top: F1 Score for the Senate from 1935-37 (74th Senate) to 2017-19 (115th Senate). Bottom: Difference between the smallest standardised P(Yi=Democrat) among all true Democrats and the largest standardised P(Yi=Democrat) among all true Republicans for the Senate from 1935-37 (74th Senate) to 2017-19 (115th Senate). F1 scores show some variability over time, but are again relatively high for all Senates (minimum F1 score = 0.8571), indicating that the GLaSS method also performs very strongly in labelling members of the Senate as Democrat or Republican. Every Senate since the 110th (2007-09) has an F1 score of 1, implying complete separation of the parties and perfect performance by GLaSS for those Senates. The Senate also experienced complete separation of Democrats and Republicans in 1983-85, 1995-97, and 1997-99 (98th, 104th, and 105th Senates, respectively). The plot of standardised differences illustrates the magnitude of overlap or separation between Democrats and Republicans in the Senate, as measured by the GLaSS method. Some negative association between F1 score and magnitude of overlap is apparent, while it is also clear that the parties are now more separated in the Senate than at any time since 1935-37