Posts tagged ‘graphs’

## Kevin Drum Inadvertently Undermines His Own Keynesianism

This is a follow-up from a post this morning here.  Kevin Drum is a Keynesian who thinks that the government is committing economic suicide if it does not increase its spending substantially during and after a recession.  Kevin Drum is also a fierce partisan who wants to defend President Obama against his detractors.  Unfortunately, trying to do the two simultaneously has led to what I think may be an embarrassing result for him.

In the chart below, I combine two graphs of his.  The one on the left is a chart from last year in a Mother Jones cover story blasting "austerity" and lamenting how dumb it was to decrease spending in the years after a recession.  The chart on the right is from the other day, when Drum is agreeing with Paul Krugman that the recession recovery under Obama has been much stronger than the one under Bush II.  The result is a juxtaposition that seems to undermine his Keynesian assumptions - specifically, the recession where we had the "austerity" was the one with the better recovery.  The only thing I have done to his charts is removed lines in the left chart for other past recessions and changed the line colors on the two charts to match.   You can click to enlarge:

The blue line is the Bush II recession, the red line is the Obama recession.  I believe the start dates are consistent in both charts.  All the numbers and choice of start dates and measurement scales are Drum's.  Don't yell at me for something in the chart construction being unfair -- they are his choices.

The conclusion?  Higher government spending seems to inhibit recovery.  Thanks Kevin!

## Graphics Fail

One of the classic mistakes in graphics is the height / volume fail.  This is how it works:  the length of an object is used to portray some sort of relative metric.  But in the quest to make the graphic prettier, the object is turned into a 2D, or worse, 3D object.  This means that for a linear dimension where one object is 2x as long as another, its area is actually 4x the other and its volume is 8x.  The eye tends to notice the area or volume, so that the difference is exaggerated.

This NY Times graph is a great example of this fail (via here)

The Tebow character is, by the data, supposed to be about 1.7x the Brady character.  And this may be true of the heights, but visually it looks something like 4x larger because the eye is processing something in between area and volume, distorting one's impression of the data.   The problem is made worse by the fact that the characters are arrayed over a 3D plane.   Is there perspective at work?  Is Rodgers smaller than Peyton Manning because his figure is at the back, or because of the data?  The Vick figure, by the data, should be smaller than the Rodgers figure but due to tricks of perspective, it looks larger to me.

This and much more is explained in this Edward Tufte book, the Visual Display of Quantitative Information.  You will find this book on a surprising number of geek shelves (next to a tattered copy of Goedel-Escher-Bach) but it is virtually unknown in the general populace.  Every USA Today graphics maker should be forced to read it.