Junk Charts

Mid-week entertainment: creme fraiche

From Forsooth! on RSS News, June 2007

Wading in waste

A poor graphic leaves readers wading in waste, in this case, the waste of time.  (Thanks to a tip from Dr. Bruce W.)

This very busy chart conveys a simple research finding, that the density of bacteria increases with the prevalence of impervious surfaces.  As Bruce pointed out, underlying this chart is but six observations taken at selected tidal creeks, each observation being a (paired) measurement of bacteria count and prevalence of impervious surfaces.

A factory worth of graphical elements was employed, including columns, pies, colors, data labels, legends and so on.  The result is utter confusion.  How is it that the tip of each column does not coincide with the center of each pie?  Do equal-sized pies imply equal surface areas?  What is the bacteria count at each location?

A scatter plot brings out the key correlation with minimal fuss.

Reference: "Wading in Waste", Scientific American, June 2006

Don't be scared of tables

I see the colors, I see the inside/outside text, I see the random distribution of slice sizes: I see variety.  But I prefer a simple, boring table.

Managing the gap

Sophisticated ideas are difficult to get across in a chart.  For instance, the NYT recently described the gender gap in the workplace by comparing the proportion of men versus women in managerial positions relative to the overall proportion.  Two simultaneous comparisons are taking place, one between men and women, and the other between managerial positions and overall employment.

The published chart (below left) used eight pie charts.  To my eyes, this graphic is confusing, not least because the primary comparison between managers and overall is set far apart.  The junkchart version (right) tries to fix this by graphically showing the gender gap using a horizontal line segment. Also, the 50% gray dotted line allows the reader to see quickly that in the three industries where men comprise the minority overall employment, they take up the majority of managerial positions.

Reference: "Stuck at the Edges of the Ad Game", New York Times, Nov 22, 2005.

Light entertainment III

From a quirky greeting cards business described as "big", "bold", "original" by FSB (Forbes Small Business).  It's called Quiplip, meaning "a witty retort and someone giving you lip", according to the founder.

Now I am curious: was she hired by Northern Trust to do their ad campaign (here and here), or are we seeing plagiarism?

Comparing Federer and Agassi

Comparability, again, is at the heart of this chart.  (Thanks Annette for bringing it up to my attention.)

 
What was attempted here was an impossible magic act, hoping to cram several disparate data series onto one chart.  It would appear that the relative age of Agassi and Federer is considered the primary control variable.  Alas, comparability is lost when the two sections were aligned by calendar year, rather than by age.  For me, it would make more sense to compare Federer at 24 to Agassi at 24; that would involve comparing 2005 to 1994, for example.

In the junkchart version (below), I use what are, at first glance, pie charts.  Ha, you muse, ain't I eating humble pie, given my repeated health warnings about pie charts?   I plead not.

 
Here, I pick the pies because of their circular shape, which has a neat analogy with the annual, four-step series of Grand Slams.  The reader does not have to judge the size of the slices or pies, only the shading and the location of each quarter-pie.  By leveraging the pie analogy, the presentation is more compact.  Compactness is a key virtue when the primary purpose of a chart is comparison; one would like to place the items for comparison as close together as possible.

As explained above, I use Age rather than Year as the variable.  Quickly one observes that Agassi skipped many Grand Slams in his early career while Federer has played almost a full slate.  They both won their first Slam at Wimbledon, both at 22 years old.  The chart signs off with an intriguing question of whether Federer's future path would mirror Agassi's.

The other half of the chart is rather easier to manage.  One would use Age as the variable and put both lines onto the same chart for compactness.

Reference: "Agassi Defies His Age; Federer Keeps on Rolling", New York Times, Sept 11, 2005.