The Dispersion Index is the average Euclidean distance from the centroid to all points on the perimeter points. The index ignores any gaps within the polygon. The Dispersion index is normalized as follows...

The Dispersion Index is appropriate to use when...

High normalized Dispersion Index values (values close to 1) indicate a phenomena that is dispersing equally in all directions. Dispersion Index results for select shapes...

Note that the Dispersion Index is not affected by gaps within the polygon ...