Graphical display of categorical data.

Categorical data are usually displayed in medical publications with pie graphs and bar graphs. We here consider some of the problems that occur in displaying the rank, magnitude, width, and spacing of categorical data. A solution to some of these problems is offered by the dot chart, which has been used in other scientific literature, but not in medical publications. The dot chart can be a preferred alternative to pie graphs and offers a useful alternative to bar graphs. Dot charts can also be helpful in displaying categorical data for two groups.