Now I found an example of what seems an even worse kind of graph… the ring or donut chart. I made the following in OpenOffice:
(the example comes from a non-published report on student admissions in Germany).
Well, the data are actually of the one kind pie charts would be suited for (taken from Wikipedia)
pie charts can be an effective way of displaying information in some cases, in particular if the intent is to compare the size of a slice with the whole pie, rather than comparing the slices among them.
For the student admission example, we have percentages adding up to 100 and we might want to visually compare the sizes of the different fractions, but even that gets blurred by the silly donut-display.
It was hard to find an even worse chart for these data, but I tried:
What do you say?