election results

Political Pie Charts

Monday, July 20, 2009 by Jon Peltier 13 Comments

Monday, July 20, 2009 by Jon Peltier
Peltier Technical Services, Inc., Copyright © 2023, All rights reserved.

In the wake of the Mark Sanford scandal, in which the South Carolina governor was accused of hiking in the Andes with his mistress or something, political blog FiveThirtyEight has published results of surveys about Sanford in Should Sanford Resign?. I was pointed to the FiveThirtyEight survey results by Andrew Gelman in Doing graphics the George Orwell way, and he got it from Should Mark Sanford Resign?. Andrew’s take is that the pie charts used by FiveThirtyEight to present the survey results weren’t as bad as they first looked.

Polling and Election Results on FiveThirtyEight

I’ve stated in this blog that the FiveThirtyEight web site uses pie charts in a very effective way. It helps that there are only two or three segments in their pies, and the third, if present, is very small. Here is a partial view of the FiveThirtyEight analysis of the November 2008 US elections.

FiveThirtyEight Pie Charts of 2008 US Election

This isn’t a full-blown Chart Busters article, but I thought I’d discuss some alternatives.

In an unfinished post from last fall, I undertook to replace FiveThirtyEight’s pies with bars, using roughly the same amount of space. The bars may have slightly better resolution, but I didn’t include a third bar for the third tiny segment. Take your pick.

Jon's Bar Charts of 2008 US Election

Survey Results

FiveThirtyEight used pie charts to illustrate the survey results. As every second grade student will tell you, pies are the chart of choice when showing parts of a whole. The educational system has trained our children to behave like sheep, and follow the herd.

Editorializing aside, these charts of the poll results are what motivated this post.

Is Mark Sanford more or less ethical than other politicians?

FiveThirtyEight didn’t even change the Excel defaults for their pie. Black chart border, ugly fill colors, and way more space everywhere than needed, especially on either side of the chart. It’s nice that the data points are labeled, but they are only partially labeled with the percentages, and the reader still must journey back and forth to the legend to see which segment means what. I also think it’s useful to put the results of a poll not in numerical order (55%-18%-18%-9%) but in some value order of the categories (more-same-less).

FiveThirtyEight Pie Chart Results of Poll on Mark Sanford's Ethics

I have redesigned the pie chart, shrinking the white space and using arguably better colors. I also reordered the points, and centered the chart differently to try to make comparisons easier.

Jon's Redone Pie Chart Results of Poll on Mark Sanford's Ethics

All well and good, but without the percentages, it’s still a guess whether More or Less had a greater response.

So I pulled a bar chart out of my magic hat. We can see that most of the cynical poll responders think Sanford’s ethics are no different than the other politicians, and equal numbers thought he was more ethical and less ethical. 9% have been busy watching Real Housewives and don’t know who Mark Sanford is.

Jon's Bar Chart Results of Poll on Mark Sanford's Ethics

Should Mark Sanford Resign?

FiveThirtyEight used another pie to show whether respondents want Sanford to resign. The colors have been changed from the gruesome defaults, but the large wasted spaces remain, as does the legend and border. Also, FiveThirtyEight didn’t use its usual style where competing results A and B meet at the vertical line at 12 o’clock.

FiveThirtyEight Pie Chart Results of Poll on Whether Mark Sanford should Resign

I’ve addressed these stylistic issues in my own version of the pie chart, and it doesn’t totally suck.

Jon's Redone Pie Chart Results of Poll on Whether Mark Sanford should Resign

Here’s the obligatory bar chart. Apparently 15% of the respondents think he should stay at the junkyard with his son.

Jon's Bar Chart Results of Poll on Whether Mark Sanford should Resign

Posted: Monday, July 20th, 2009 under Chart Busters.
Tags: election results, Pie Charts, survey results.
Comments: 13

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An Undistorted Election Results Map

Friday, November 14, 2008 by Jon Peltier 4 Comments

Friday, November 14, 2008 by Jon Peltier
Peltier Technical Services, Inc., Copyright © 2023, All rights reserved.

In Redrawn Electoral Maps I wrote about cartograms which selectively expand or contract regions of a map according to population, in order to give the map a more balanced weighting than geographical surface area. This has actually been a very popular blog topic in the past few weeks, especially because of the US presidential election. While these maps preserve the topology of the states that make up the US, some people do not like the sometimes severe distortion of the geographical regions. Personally I don’t mind the distortion of the states, but when a cartogram drills down to the county level, I lose the ability to relate to it.

Nathan of Flowing Data first showed me the electoral cartograms, and also led me to the following approach.

Andy Woodruff has written about an approach Axis Maps has developed which does not distort the geographical geometry of the map, in A new kind of election map and also in I hate your favorite election map in his personal blog. This visualization approach keeps the map undistorted, but uses shades of red and blue to shade counties according to their population.

Map of 2008 Presidential Election Results, Shaded by Population

This is an interesting approach. I have had some difficulties interpreting this map (here is a larger version). First, the preponderance of black distracted me. I had the feeling of floating in space above disconnected objects.

Second, when I see different shades of color in a map, my first inclination, ingrained by staring at thousands of maps, is to interpret the different shadings as a measure of some sort of density. Population density, perhaps, or comparative strength of the vote in that region for one candidate or the other.Using color for total population of a county is integrating population density over the square miles of the county.

Another issue is comparing brightness of different regions. If two regions are abutting, and surrounded by a uniform third color, it is easy to compare their shades. If however the two regions are located at a distance and surrounded by different swatches of colors (say, Detroit and the region NE of Los Angeles in the map above), then I challenge anyone to compare their shades accurately. In Practical Rules for Using Color in Charts Stephen Few illustrates the difficulty of comparing colors of regions that are surrounded by different shades.

In general, I’m not opposed to this visualization approach. I think with a little development it may actually be practical. What we should keep in mind while comparing all manner of visualization techniques is what Andy said to me, when I described my difficulties with these charts, both area-distorted and color intensity-distorted, is that:

It’s a matter of taste and other personal factors.
In the end, neither map is really going to provide observations more qualitative that “there’s more blue in this area than that area.”

I could not have said it better.

Update:

As I ruminate on these charts, I have thought of a couple enhancements that may help make them more instantly comprehensible: Use a white background instead of black, and draw in the state boundaries, especially if the map shows separate shadings down to the county level. Perhaps Andy may humor me and toss out a couple samples?

Posted: Friday, November 14th, 2008 under Chart Types.
Tags: election results.
Comments: 4

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Redrawn Electoral Maps

Thursday, November 13, 2008 by Jon Peltier 2 Comments

Mark Newman, of the Department of Physics and Center for the Study of Complex Systems, at the University of Michigan, shares some interesting views of the recent US presidential election results in Maps of the 2008 US presidential election results.

The states won by Republican candidate John McCain seems to dominate the regular map, even though Democratic candidate and president-elect Barack Obama controlled the Electoral College results.

Map of 2008 Presidential Election Results, Scaled to Area

But the map above is based on area, not on the amount of voters. The Northeast and California have relatively high population densities, while many of the rectangular states in the middle of the country are less densely populated. Mark creates “cartograms” which distort readjust the areas of geographical units to reflect other quantities besides land mass area (“distort” is such an ugly word, normally reserved here for 3D charts).

The cartogram below adjusts the areas of the states so each is proportional to the population of that state. Notice how most of the red states in the middle of the map have shrunk, particuarly in the northern plains. The Northeastern stats and to a lesser extent California have expanded, and the colors on the map match the election results. My boyhood state of Rhode Island is larger than Wyoming (even DC is larger than Wyoming), the Dakotas, and Montana. If Alaska were on this map, it would also be dwarfed by Rhode Island.

Map of 2008 Presidential Election Results, Scaled to Population

Pretty cool. The shapes of the redrawn geographical units are still recognizable, and you come away with a better sense for distribution of votes. On his web site, Mark shows more views of the results of this and previous elections, as well as cartograms based on other measures.

Posted: Thursday, November 13th, 2008 under Chart Types.
Tags: cartograms, election results.
Comments: 2

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Re: Graphical Propaganda

Thursday, July 10, 2008 by Jon Peltier 1 Comment

In More graphical propaganda, Andrew Gelman of the Statistical Modeling, Causal Inference, and Social Science blog shows some pie charts of recent Kenyan election results which he got from John Sides’ blog post, Election Fraud in Kenya in The Monkey Cage blog. The charts are awful; as Andrew notes, the colors change and the wedges are reordered. I’ve regraphed the data on a bar chart, which I think is much better.

Original Chart

Kenya Poll Pie Charts