Area vs length
I was listening to the TAL/Propublica report on the hedge fund Magnetar and went to their website which shows bubbles of the size of CDOs which Magnetar invested in vs. the market total of similar CDOs.
Long ago, Cleveland and McGill showed that people are better at comparing length than at comparing areas, but still you’ll see bubbles (saving space perhaps). Below you can compare two presentations of the same data.
Here is one row from the original chart:
And the same data as a stacked barchart:
Also, it seems the black circle is the total size of the CDO which Magnetar had a part in creating, not the actual amount that Magnetar invested, but the legend has a black circle with just the word ‘Magnetar’ printed next to it.