Ranks have lots of problems. They’re statistically unstable (see the work of Tom Louis) and can mask nonlinearity. I was recently reminded of these patterns in seeing two sets of graphs reproduced by Kaiser:
From the Wall Street Journal, graphs of baby names over time:
The graphs are ok but plotting ranks, rather than proportion of total names each year, is a mistake, since it makes the y-axis extremely hard to interpret, it’s not clear where zero is, etc. As Kaiser points out, in any case there are difficulties when the scales are different for different plots, but, beyond this, the ranks are making things tougher.
And, from the New York Times, a summary of problems with the subway lines:
Here, the ranks are giving a hyperprecision that is not helpful. (Also, encasing the subway line numbers/letters in black circles makes them harder to read, at least on the screen.) As some commenters pointed out, it would probably be better to just display each line with three or five grades, sort of like how Consumer Reports does the ratings.