Other such measures include the statistical range, the interquartile range, and the average absolute deviation, and, in the case of categorical random variables, the discrete entropy. None of these can be negative; their least possible value is zero.
A measure of statistical dispersion is particularly useful if it is location invariant, and linear in scale. So if a random variable X has a dispersion of SX then a linear transformation Y = aX + b for real a and b should have dispersion SY = aSX.
See also summary statistics.