a measurement of a variable’s association with itself throughout space. Although statistical approaches often assume that measured outcomes are independent of each other, this may not be true for observations made at different locations. For example, measurements made at nearby locations may be closer in value than measurements made at locations farther apart. Spatial autocorrelation thus provides an index of the similarity of objects within an area, the level of interdependence between the variables, and the nature and strength of that interdependence. See also autocorrelation.