Variation ratio

The variation ratio is the percent of cases which are not the mode. This may be used as a measure of dispersion for nominal variables, notable because some texts and guides suggest or imply that the dispersion of nominal measurements cannot be ascertained.

Just as with the range or standard deviation, the larger the variation ratio, the more differentiated or dispersed the data are; and the smaller the variation ratio, the more concentrated and similar the data are.

For example, a group which is 55% female has a variation ratio of 45% and is more dispersed in terms of gender than a group which is 95% female and has a variation ratio of only 5%. Similarly, a group which is 25% Catholic (where Catholic is the modal religious preference) has a variation ratio of 75% and is much more dispersed religiously than a group which is 85% Catholic and has a variation ratio of only 15%.