The value of explanations

I did a small experiment on some of my classmates yesterday, looking at the value of explanations in graphs: what happens if I remove the title and explanation of a graph and give it to someone outside of the field of infographics?


Vis 1: Edward Tufte’s slopegraph of cancer survival rates (edited by Dave Nash) (slopegraph)

In the top-right corner of the paper sheet I had written “survival rate %” – although this is to some extent an explanation of the graph, the group still struggled to get what they were looking at. They ended up never completely understanding the graph, which in turn made them only talk about how to read it, and not discuss the content. When I explained what the graph was showing and how it should be read, they felt the visualization was to complex and  that it should have been visualized in a different way. Maybe because slopegraphs are still not that common?


Vis 2: The Description of a Slave Ship (construction drawing)

The group understood the content of the graph very quickly. Without any words or numbers in it, they still found it very interesting to look at – though they did mention that it would be nice with numbers that could emphasize the visual content. Most of us are used to looking at construction drawings, and this might be the reason to why they had so little problems with reading the visualization. What is also interesting is how they thought it was a modern visualization made to look old (the content is even more shocking if you know when it was made), and how much they appreciated that the people in the visualization were drawn differently (not just the standard illustrator man icon).


Vis 3: Bears by Stephen Wildish (venn diagram)


The group did NOT like this diagram. Until now they had been given visualizations with a serious and complex content. It was a lot of fun listening to how they tried to come up with what useful content this diagram was displaying. Since they did not know anything about venn diagrams, they did not understand how to read it – why was the grey area smaller than the black and white, and did the size of the circle mean something? They found the diagram extremely difficult, and did still not understand it when they got the original version with an explanation of how to read it. The group did not find it funny, but stupid, useless and unnecessary. Maybe in a different situation where the group were expecting a funny, simple diagram they would have enjoyed it?


Vis 4: Raining A Deficit – the last fifty years of rainfall in downtown San Francisco by Stephen von Worley (bubble chart)

This time the group had difficulties with understanding the labels and the color scheme – why brown/green? And what’s the “Before/After”? They immediately got caught up in the “Valentine’s Day” label (“What does Valentine’s Day have to do with anything?”) – if it’s not related to Valentine’s Day, why the label?  This shows how important these small explanations are, and how important it is that they are carefully thought through.  In the end they understood how to read the graphic (to a certain extent). Two of them said that they didn’t find it interesting, and the last one thought it was interesting because it was nice to look at.


Vis 5: Napoleon’s 1815 March on Moscow by Charles Joseph Minard (flow map)

 This is one of the world’s most famous graphics, declared by Edward Tufte to probably be the best statistical graphic ever drawn. I believe I removed to much information this time, making them depend very much on the little amount of information they got (like the word “rain” that I kept, because I forgot to remove it). Again, this shows the importance of thought through explanations. Here is a video of how the group did (they didn’t get it):


Vis 5.1:  Re-vision 1

Will it be easier to understand the graphic if they see another version of it? Does it help when the graphic is placed on a map?



Vis 5.2: Re-vision 2 by John Boykin

Will it be easier to understand the graphic if they see another version of it? How will they respond to seeing the graphic as a circle?



Maybe I went a bit far and took out too much information this time, making the group spend most of their time trying to figure out the graphics. Also, the group didn’t decide how much time to spend on each graph (this happened unconsciously) – I should have told them in the beginning that they decided how much time to spend on each example (not interesting – let’s move on to the next one).

In the future it would be interesting to experiment with different levels of explanations (as proposed by Bas (Interactives) here).

Those interested in information visualizations probably know about the discussions of the hard balance between an informative and a decorative infographic (read my previous post here). Although this experiment isn’t really a response to the discussion, it can easily be related to it.


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