Thursday, February 19, 2009

Statistical Modeling, Causal Inference, Social Science, and … where is my Comment?

Here is what Andrew Gelman posted on his blog:

I have never ever seen an example where I’ve felt a boxplot was appropriate. I’m open to being convinced, but I don’t think you’ll be able to convince me. Bring on the examples!

You can imagine that I can’t really agree with him, and I guess that the Tour de France examples posted on this blog are at least one counterexample showing the flexibility and usefulness of boxplots. There are certainly some drawbacks of the design (symmetric whiskers, very large data, …) but over all, boxplots are as simple as versatile - who would dare to ignore this.

Feel free to comment, I promis, I won’t censor your comments … 
Posted by Martin at 20:35:27 | Permalink | Comments (1) »

Tuesday, November 14, 2006

The Good & the Bad [11/2006]

This time it is easy for me, as I just need to point to the interesting discussion at Junk Charts.

The original graphics is from the NYT:

The “improved” plot looks like this:

The advantages of the box-plot view (from Junkcharts)

  • The European market is much more fragmented than the U.S. market.
  • The Big 2 (GM, Ford) has had mixed fortunes over this period (as indicated by the large variance)
  • The Big 2 are competitive in Europe although they are definitely not dominant there
  • Several key players in Europe (Peugeot, Renault, Fiat, BMW) have negligible shares in the U.S

The discussion was quite lengthy, but had the two major points:

  • Boxplots are too hard to read for NYT readers
  • The boxplots ignore the temporal information and thus are not really suitable for this data

One important point was not mentioned explicitly, which is

  • Sorting is a very powerful and important option in graphics

There is truth to all the issues raised here, and the bottom line is probably that there might be not a single graphical view on the data which covers all aspects of the data. Furthermore, the NYT graphics is by far the most eye-pleasing version of all suggestions.

In this spirit I want to throw in two more versions which show the data:
Two variations of Mosaic Plots (will be explained in the next ’statistical graphics 101′) in the multiple barchart view. European cars are highlighted:

(Year x Brand x Continent)

(Continent x Brand x Year)

 

Posted by Martin at 19:30:50 | Permalink | Comments (3)