Can We Improve this Graphic Showing History of Bipartisan Senate?

February 28, 2008  |  Statistical Visualization

David forwarded me his graphic on the modern two party system in the United States senate which essentially shows the senate's bipartisanship over time. It made me happy to see someone in political science using R, playing around with data, and taking a stab at creating a useful graphic.

Improving the Graphic

While the graphic is indeed useful, I think there are some things that could make it even better. Here are thoughts that I sent to David.

  • 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.
  • 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.
  • 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)?
  • 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?
  • It might be worth making the annotations bigger so that you don't have to "zoom in" to read.
  • I think I would make the median lines a bit more prominent, but that's just me.
  • 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?

Now It's Your Turn

So that's my opinion. What do you think? Judging from our FlowingData Facebook group (which I'm happy to see is growing), we have a very diverse bunch from design, statistics, computer science, and some other areas, so I'm eager to hear what the rest of you think about this visualization.

4 Comments

  • 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.

    Thanks again very much for your interest and comments. I really enjoy the blog, and sincerely appreciate any advice or suggestions anyone may have.

  • Initial thoughts…

    — I love the idea that you can see the movement of individual states on the left-right scale. Just see how Oregon becomes more and more left oriented from 1950-1967. (sanity check… something is wrong in my understanding)

    — Using red and blue to represent Democrats and Republicans makes sense, but what are all the hues.

    — Yellow on white? whats up with that?

    — Does the yellow markers (triangles and circles) and the yellow data points have anything to do with each others?

    Trying to understand the graph…

    — Since each state have more points in each year, each point can clearly not represent a state — maybe is is actually representing individual members of the senate.

    — The gray curve must represent the overall balance in power. (is it a derivative of only the red and blue, or is there a third factor involved: weighted by how many democrats and republicans are elected)

    — The Marilyn Monroe on her back distributions / peaks at the bottom represents some kind of unity within the senate and within each party. But what is the wave that seems to run from peak to peak over the span of decades?

    — Color indicates size and party of majority. So the majority is either blue or red, but I see a whole lot of purple. Is majority a quantifiable measure (I have a big majority), or is it a boolean quality (I do not have majority)? When it comes to voting even the smallest majority is a big difference.

    — I like the idea that senators grow bigger over time, representing a believed increase in power. Personally I am not sure that the older guys is always more correct and/or influential.

    Improvements…

    — I would like to see the name of each senator (possible just in a mouse over). Who is that Oregon senator that swings left in the fifties? Possibly also see all other data points representing him. Did my senator make any drastic shifts in politics?

    — How is the left-right scale determined? It is vital to the understanding of the concept that this value gets explained in a creditable way. Here in Europe a lot of new parties (yeah, we got more than two :-)) are trying to define them selfs as not on a left-right scale (that must of them have great problems doing so is another story).

    — The majority gradiant. It seems like majority is a linear gradient between large and small. I believe it could be represented much better if you take into account the qualitative shifts along the scale. Less purple, and a big difference from 49, 50 and 51 senators on your side.

    — I am not sure about the significance of senators from southern states. Why is this still an issue?

    — No yellow on gray. It is unreadable.

    — I think the difference in ideological score from senate median to president is rather interesting, but is is very hard to spot the presidents (a US datapoint with a yellow circle)

    — The relative heights of the peaks from one year to another in the bottom distributions promises some kind of meaning, but I don’t seem to find any.

    Conceptual improvements…

    — I am not sure I am in favor of the display all information everything in one picture. I believe the data could be represented better with a more pictures with individual focuses. Maybe add a few miniatures to the graph with some info left out and focus on other.

    — Scripting complete graphs. I don’t think it is possible to do a complete illustration in R, Gnuplot, excel or other graph drawing programs (bold statement). I consider the plots as an easy way to get the dimensions correct, data points positioned, develop an understanding of the data at hand and do raw sketches. When it comes to creating illustrations, I would move my sketches into Illustrator, Inkscape, Flash or similar and then draw them up. If I have to create interactive illustrations I would most likely go to a full blown programming language, in most cases Java.

    — Representing values in colors. Heat maps and a-like has its place and time, but sometimes color gradients does not read very well, especially the famous rainbow gradient. More or less red or blue looks like shades of purple to me, and unfortunately my mind is stuck in a 16 color scheme. Is peach and salmon the same color?

    — Layering. Edward Tufte has some great thoughts on visual layering, and I think the graph could benefit from some of the ideas. The gray bands are clearly behind the data and belongs to the graph paper layer. Good. The data points and the three curves fight about the data layer. Less good. The bottom purple boxes stands out as on-top. Bad. I don’t think you can how much more then one data layer per graph. So maybe miniature multiples with difference layering could be a solution.

    — Displaying 150 years of data on a timeline is rather impressive. I think the graph could benefit from some hooks in time. Some illustrations like World Wars, famous presidents, moon landing, assassination would improve the readability.

    — Up and down, left and right. I imagine my self walking along a middle horizontal axis (-1 is down, 1 is up, 0 is middle) through time (left is early, right is into the future). If I sway up, towards 1, from my perspective it would be a left to me. On the graph pictured, swaying up represents a movement to the right. Maybe flip the vertical axis?

    Thanks for a great find and all the room for improvement. I am looking forward to see the future versions. I am thrilled to have found this great blog, but I am sorry I will not head over to facebook to join you all…

  • basically, it just comes down to making the graphic cleaner, because right now it’s a little too busy for me to handle.

  • Tim Reeves July 30, 2008 at 6:34 pm

    I don’t get the majority numbers. If “2″ is a possible majority, then I think it means 51-49 (the difference). If “64″ is a possible majority, I think it means 64-36 (the majority size). How are the two methods compatible?

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