Here is an example, based on Problem 2.40 from "Statistics and Experimental Design in Engineering and the Physical Sciences," by Johnson and Leone.
A Roper Report issued in 1974 estimated that citizens (in the percentages indicated below) would not object to (1) a government agency filling a sensitive job, (2) a private company, (3) local police, or (4) a "credit card company" having the following data:
(1) (2) (3) (4) Employment records 74 64 27 44 Psychiatric history 66 38 34 10 Health records 64 50 25 13 Memberships, Associations 53 20 22 7 Traffic violations 43 19 50 8 Tax returns 39 13 15 10 Sexual history 31 12 20 5
Represent these data pictorially, and comment.
A typical way is a clustered column chart (Excel's term). But which way to cluster?
In either case, it is sort of easy to compare within clusters, but less so across clusters. The color helps, but in either case things are cluttered. The separated legend requires you to look back and forth.
The thermometer plot has a 3-D layout for this 3-D data.
I find it easy to scan the rows and the columns in this plot.
Other 3-D arrangements I've seen use either scaled bubbles or pie charts instead of thermometers. The problem with bubbles is that the scale is not so intuitive; do you scale the bubbles by radius or area? (Excel offers both options.) The thermometer varies cleanly in one dimension. Which is easier to read than the angles in pie charts.
Of course, the thermometers can also be used to plot a third dimension on an x-y-z plot or on a map, rather than a regular grid of categories like this example.
The example thermometer could be done in Excel.
But not so easy to put them on an x-y-z plot or a map.