Vizzy vizzy vizzy viz

Nadia Hassan points me to this post by Matthew Yglesias, who writes:

Here’s a very cool data visualization from HowMuch.net that took me a minute to figure out because it’s a little bit unorthodox. The way it works is that it visualizes the entire world’s economic output as a circle. That circle is then subdivided into a bunch of blobs representing the economy of each major country. And then each country-blob is sliced into three chunks — one for manufacturing, one for services, and one for agriculture.

world-economy-gdp-voroni-a7d4.0

What do I like about this image and what don’t I like?

Paradoxically, the best thing about this graph may also be its worst: Its tricky, puzzle-like characteristic (it even looks like some sort of hi-tech jigsaw puzzle) makes it hard to read, hard to follow, but at the same time gratifying for the reader who goes to the trouble of figuring it out.

It’s the Chris Rock effect: Some graphs give the pleasant feature of visualizing things we already knew, shown so well that we get a shock of recognition, the joy of relearning what we already know, but seeing it in a new way that makes us think more deeply about all sorts of related topics.

As a statistician, I can tell you a whole heap of things I don’t like about this graph, starting with the general disorganization—there’s no particular way to find any country you might be looking for, and there seems to be no logic to the spatial positions—I have no idea what Austrlia is doing in the middle of the circle, or why South Korea and Switzerland are long and thin while Mexico and India are more circular. The breakdown of economy into services/industry/agriculture is particularly confusing because of all the different shapes, and for heaven’s sake, why are the numbers given to a hyper-precise two decimal places?? (You might wonder what it means to say that Russia is “2.49%” of the world economy, given that, last time I checked, readily-available estimates of Russia’s GDP per capita varied my more than a factor of five!)

Yglesias’s post is headlined, “This striking diagram will change how you look at the world economy,” and I can believe it will change people’s understanding, not because the data are presented clearly of because the relevant comparisons are easily available, but because the display is unusual enough that it might motivate people to stare at these numbers that they otherwise might ignore.

Some of the problems with this graph can be seen by carefully considering this note from Yglesias:

You can see some cool things here.

For example, compare the US and China. Our economy is much larger than theirs, but our industrial sectors are comparable in size, and China’s agriculture sector looks to be a little bit larger. Services are what drive the entire gap.

The UK and France have similarly sized overall economies, but agriculture is a much bigger slice of the French pie.

For all that Russia gets played up as some kind of global menace, its economy produces less than Italy. Put all the different European countries together, and Russia looks pathetic.

You often hear the phrase “China and India,” but you can see here that the two Asian giants are in very different shape economically.

The only African nation on this list, South Africa, has a smaller economy than Colombia.

What struck me about all these items is how difficult it actually is to find them in the graph. Comparing the U.S. with China on their industry sector, that’s tough: you have to figure out which color is which—it’s particularly confusing here because the color codes for the two countries are different—and then compare two quite different shapes, a task that would make Jean Piaget flip out. The U.K. and France can be compared without too much difficulty but only because they happen to be next to each other, through some quirk of the algorithm. Comparing China and India is not so easy—it took me awhile to find India on this picture. And finding South Africa was even trickier.

My point is not that the graph is “bad”—I’d say it’s excellent for its #1 purpose which is to draw attention to these numbers. It’s just an instructive example for what one might want in a data display.

The click-through solution

As always, I recommend what I call the “click-through solution”: Start with a visually grabby graphic like this one, something that takes advantage of the Chris Rock effect to suck the viewer in. Then click and get a suite of statistical graphs that allow more direct visual comparisons of the different countries and different sectors of the economy. Then click again to get a spreadsheet with all the numbers and a list of sources.

11 thoughts on “Vizzy vizzy vizzy viz

  1. Well, South Africa was not so difficult to find cos as the only African country on thee it is the one in the color category that has only one member. Though why is it South Africa? I thought Nigera had surpassed it after a massive adjustment of their NGDP calculation (perhaps the data were not precise enough to give two places after the comma, ho, ho).

    Their homepage tells me that this is a Voronoi diagram. Though I’d be interested to know why they themselves thought it would be a good idea to display the data that way and not, say, as a bar plot.

  2. So, the Rest of the World borders on the USA, Canada, UAE, and Austria but not China or Brazil. That is a harbinger of future growth for North America. And the nations that will then rule it.

    People love random, spurious association, e.g. astrology. And statistics! (Ooops, sorry! Bad statistics prospers; the good stuff struggles to be heard.)

  3. The most salient message in this weird pie-like graphic – the one that’s so easy to see that it jumps out at you – is that the US and China have the biggest economies. I think we knew that.
    I redid the data with a scatter plot overlaid on a violin chart. Then I learned something that really did amaze me: The economies of the countries in this data are way more similar than they are different in terms of the distribution of service/industry/agriculture.
    Take a look: https://drive.google.com/file/d/0B2B00XYDJi4uSGRud0pXUTdGcVk/view?usp=sharing
    PS: Please forgive the color coding if you don’t like it. You may be right, but this is a 15 minute quick look, and I know it could be improved.

  4. One thing that bothers me is that the way the sectors are joined makes it look a bit three dimensional. I like that area represents proportion but I wonder if the way the ration of lengths of the different axes to each other is varying creates some misperception. Some of the agricultural areas look like blank space to me rather than information. It seems like the focus was more on having a circle than on readability.

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