Alex Lundy writes:
I’m an avid reader of the Monkey Cage, and as such, I wanted to point you towards a data-visualization I’ve just completed based upon Martin-Quinn scores, the numeric ideological estimates for Supreme Court justices developed by political scientists Andrew Martin and Kevin Quinn.
This is beautiful. My main comment is that I don’t know whether to believe the numbers. Is the Anthony Kennedy of 2007 (ideology score 0.14) really so close to Hugo Black in 1970 (ideology score 0.06)? To look at it another way, according to these numbers, in 1973 (the year of Roe v. Wade), six of the justices are colored red and the median justice is listed at 0.67. In 2007, only five are red and the median is at 0.14. In fact, in 2005 the median is listed as -0.07, or slightly to the left of center. Is it really plausible that the court was more liberal in 2005 than in 1973? Maybe so, but something looks fishy to me here.
Spaeth’s numbers (for each justice, the proportion of cases for which he or she voted on the conservative side; see Aleks’s graph here) look a bit more reasonable to me, although I know these numbers have issues too. See here for further discussion.
Beyond this, I have a few comments on the display:
1. I’d prefer some sort of continuous color labeling rather than the red-blue labeling that Lundry is using. When you’re mapping votes, it makes sense to use votes that are more than 50% in one color and less than 50% in another. But for these judicial ideology scores, the 50% point is pretty arbitrary, and I think it’s misleading to jump from red to blue.
2. I think it’s misleading to line up the justices in positions #2, 3, 4, etc, thus implying some sort of continuity between retiring judges and their replacements. When a new judge comes in, he or she is really coming in anew, and I think it would make sense to add a new line for him or her rather than creating an illusion of continuity. In particular, the values on the far right column of the table (with the exception of the chief Justice) are basically meaningless.
3. Supreme Court years are of the form 1970-71, 1971-72, etc. In the current labeling, it is unclear whether “1972” refers to 1971-72 or 1972-73. It would be easy to fix this by shifting the year labels to be between the blocks.
4. Justice Hughes’s middle name is misspelled. More generally, I can’t figure out what his rule is for when to include middle names, when to include middle initials, and when to include neither.