A few days ago, I posted a history of partisanship in the Senate, which you should check out if you haven’t, it’s pretty fancy. Nathan Yau, author of the blog FlowingData, posted a helpful critique on his blog. I responed in the comments, and reproduce those comments below. If you have any comments or suggestions, please let me know. I am trying to optimize it, and any feedback is useful.
Thanks a lot for soliciting comments. You raise a lot of good questions here, I thought I might try to respond to some of them. My answers aren’t the final answer, mostly I’d like try to do an initial justification of some of my design choices:
* I wasn’t immediately sure what each visual cue represented e.g. size of state abbrev. until I reached the bottom. It might be worth making the annotation more prominent either by position, size, or color or all three.
This is a pretty good point. It may help to move the key. Mostly, I put it at the bottom to minimize its obtrusiveness.
* To me, the congress numbers don’t matter so much, but that just might be I don’t have a lot of learning on the history of American government.
The congress numbers and years are in some ways redundant, but congress scholars often refer to congresses by their number. In fact, the years are only there for those less familiar with the congress number, to give a sense of where you are in history.
* I’m wondering if there’s some way to make the labeling of the years more concise? If you just labeled with the first year of the two-year term, would it be obvious that you’re describing a two-year term? What if you took away the alternating gray background and just made it all white and then had a bar timeline-type thing on top (and bottom)?
I may be able to do without both years, since it is known that there are always two years to each congress. The gray and white bars are somewhat useful, because it’s not labeled (it should be), but within each session, the points all have a certian left-right jitter–this jitter makes it easier to read, and actually conveys in a very subtle way the second dimension of the ideological scale on which each Senator is plotted. If you read more about DW-nominate, you will find that the primary dimension dominates, but for certain time periods, a second dimension becomes important. I thought I would include it subtly, because it also helped with readability.
* What if you tried to use a color scheme? I mean, you have the red and blue for the reps and dems (which I think is right), but the gradient for the senate counts turns very bright pink and purple which doesn’t go too well. Then there’s the cyan, yellow, and green which doesn’t seem to have any specific significance other than each color represents something. What I mean is… is there a reason you chose those colors?
The colors chose themselves: red and blue have come to be identified with each of the parties. Green was my remaining option out of the RGB set, and I made all Southerners’ green value equal to 255. Then, every Democrat’s B value varies as a function of their party unity (the degree to which they voted with the party). The same for Republicans and Red. Thus you can read members’ party loyalty into their color. The interesting thing is, disloyal northerners look dark, even blackish, but disloyal southerners’ lack of R and B makes them increasingly only green. Thus, for example, the very disloyal Southern Democrats of the mid-20th Century can obviously stick out as very green, where other Southern dems are various shades of teal and greenish-blue. This reflects a very important shift in the history of Congress, and it’s all indicated right there, just as a function of geography and loyalty transformed to color values.
* It might be worth making the annotations bigger so that you don’t have to “zoom in” to read.
Also possibly valid, although part of the reason I made them small is that my original intent was to design for print, where the poster will be about 24×36 inches, and the labels will be fairly legible.
* I think I would make the median lines a bit more prominent, but that’s just me.
Not a bad idea, but I a) don’t want them to completely dominate, and b) want to maintain legibility of the overlaid state names as much as possible. I may be able to make the medians wider, but then in a sense, one loses accuracy.
* There’s a lot of cool stuff getting represented here, and I wonder if anything might benefit as a separate graph. Would this benefit at all as a series of graphs instead of one large graphic?
Possible, except one of the things I like most about it is that it tells almost the entire story of partisanship and something called conditional party government (which relates to the density graphs at the bottom), all in one place. So it’s a very comprehensive and relatively quick way to get all of it “at a glance” if you know what to look for.