Politics in 2015 were largely been defined by polarization; the GOP presidential race is once again devolving into a fight of the extreme right versus the moderate establishment and the Democratic presidential race is seeing a race to the left by all three candidates. Amidst the spectacle of the presidential primary, the House of Representatives also experienced a polarizing year. Most notably, last year saw the rise to prominence of the House Freedom Caucus in the aftermath of John Boehner’s resignation as Speaker of the House. In our analysis of the House Freedom Caucus, we developed a metric called the Dissent Importance Index, or DII, to measure how important of a force a member of the House when they break the party line. To calculate the DII for a representative, we look at every roll call vote which is available on the House Clerk’s website and assign it a DII number. If the representative sides with their party leader,1 then for that vote, their DII is zero. Similarly, if the representative is the only person in the chamber who votes one way, their DII is zero.2 Using this situation as one endpoint, we define an linear relationship3 between the margin of the vote and the DII, meaning that a smaller margin means a larger DII for that vote.4 Summing the DII for every vote of a representative5 and dividing by their total number of votes, we get a DII average. This metric is not perfect, and like most statistics, means very little in a vacuum. However, in context, when compared to other representatives, the DII becomes a way to measure how often a particular representative breaks the party line in important votes when compared to their peers.
Well DII tells us about the inclination to dissent of a representative, their political ideology is also often important when evaluating representatives. One of the most well-renowned metrics of political ideology is the DW-Nominate score, calculated by Howard Rosenthal and Keith Poole at the Department of Political Science at the University of Georgia. The first-dimension of this score can be roughly translate into the congressperson’s ideology, with a negative score being more liberal and a positive score being more conservative.
In order to allow you to see both the DII and the DW-Nominate values for any member of Congress, we have created the following tool. There is a search box and by clicking on any of the headers, you can sort the table. Furthermore, below the table, you will notice a graph. Initially the graph just shows the DII plotted against the DW-Nominate score for all representatives (where red dots are Republicans and blue dots are Democrats). If you click a representative in the table, you will see their dot highlighted in the graph. We hope that you can use this tool to see how your representative did and that this may allow you to become more infomed as we enter the new year! Enjoy!
|First Name||Last Name||District||Party||DW-Nominate||DII-Average (All)||DII-Average (Bills)|
Footnotes [ + ]
|1.||↵||We assume that the party leader solely determines the party line with their vote&emdash;perhaps a bit of a leap, but it is probably the only way to determine the party line. If you have a better idea, please, let us know in the comments!|
|2.||↵||The thinking here is whether or not they broke the party line, the vote would have turned out the way it did, so their dissenting vote is virtually meaningless.|
|3.||↵||Techically, it is an affine relationship.|
|4.||↵||Specifically, DII = (-0.463)*margin + (100.463)|
|5.||↵||It is worth noting that the votes on the roll call do not capture every vote made by the representatives, only the ones for which the yeas and nays are called. While this means that it does not represent every dissenting vote, it still allows the DII average to be used as a way to compare representatives.|