McCutcheon index

The McCutcheon index or chemotactic ratio is a numerical metric that quantifies the efficiency of movement.

It is calculated as the ratio of the net displacement of a moving entity to the total length of the path it has traveled.

A value close to 1 indicates that a moving entity performed its movement in a very direct manner, minimizing detours.

On the other hand, a lower value indicates that the entity has achieved only a marginal net displacement, despite traveling a considerable distance.

[3] It is named after Morton McCutcheon who introduced it to describe chemotaxis in leukocytes.