Vanity heights and scary charts
Sep 19, 2013
Sometimes I wonder if I should just become a chart doctor. Andrew recently wrote that journals should have graphical editors. Businesses also need those, judging from this submission through Twitter (@francesdonald). Link is here.
You don't know whether to laugh or cry at this pie chart:
The author of the article complains that all the tall buildings around the world are cheats: vanity height is defined as the height above which the floors are unoccupied. The sample proportions aren't that different between countries, ranging from 13% to 19% (of the total heights). Why are they added together to make a whole?
The following boxplot illustrates both the average and the variation in vanity heights by region, and tells a more interesting story:
Recall that in a boxplot, the gray box contains the middle 50% of the data and the white line inside the box indicates the median value. UAE has a tendency to inflate the heights more while the other three regions are not much different.
The other graphic included in the same article is only marginally better, despite a much more attractive exterior:
This chart misrepresents the actual heights of the buildings. At first glance, I thought there must be a physical limit to the number of occupied floors since the grayed out sections are equal heights. If the decision has been made to focus on the vanity height, then just don't show the rest of the buildings.
Also, it's okay to assume a minimal intelligence on the part of readers - I mean, is there a need to repeat the "non-occupiable height" label 10 times? Similarly, the use of 10 sets of double asterisks is rather extravagant.
I'm still not really sure what the percentage vanity height means. Is it the percentage of the height of the building, measured from the top down, that is unoccupied?
If so, maybe the box plot should be "hanging" upside down to show the right direction, the same as when we insist on time going left to right, not right to left or vertically.
Posted by: derek | Sep 19, 2013 at 04:33 PM
For the last chart, the designer missed an opportunity here. Drawing the actual buildings side by side could be a very nice direct comparison. The vanity portion could be coloured differently in each case.
Posted by: Bob | Sep 19, 2013 at 10:49 PM
I'm completely baffled by the pie chart. I can't tell at all what even the intention was.
Posted by: mp | Sep 23, 2013 at 03:24 PM
Hi there, I was curious to know which data you used to generate your boxplot?
Other than that, great blog!
Posted by: StatPat | Oct 28, 2013 at 02:09 PM
StatPat: That chart was created in JMP Graph Builder.
Posted by: Kaiser | Oct 28, 2013 at 10:42 PM