手法を比較

	Nearest Neighbour Index	Spatial Exposure Index
分野	Human Geography	Human Geography
系統	Process / pipeline	Process / pipeline
提唱年	1954	1954
提唱者	Philip J. Clark & Francis C. Evans	Wendell Bell (P* indices); Douglas Massey & Nancy Denton (segregation dimensions)
種類	Summary statistic for the degree of clustering or dispersion in a point pattern	Segregation measure of the potential contact or isolation between population groups
原典	Clark, P. J., & Evans, F. C. (1954). Distance to nearest neighbor as a measure of spatial relationships in populations. Ecology, 35(4), 445–453.	Bell, W. (1954). A probability model for the measurement of ecological segregation. Social Forces, 32(4), 357–364.
別名	Clark-Evans Index, Nearest Neighbour Analysis, NNI	Exposure Index, Isolation Index, P-star Index
関連	4	4
概要	The nearest neighbour index, introduced by Clark and Evans in 1954, is a simple summary statistic that quantifies whether a set of points is clustered, randomly scattered, or evenly dispersed across an area. It compares the average distance from each point to its closest neighbour with the average distance that would be expected if the same number of points were placed completely at random. The ratio of observed to expected distance, together with a significance test, gives a single interpretable number that has become a staple of point-pattern analysis in geography and ecology.	The exposure and isolation indices, written P*, measure residential segregation as the degree of potential contact between population groups across the neighbourhoods of a region. Developed by Wendell Bell in 1954 and later codified by Massey and Denton in 1988 as the 'exposure' dimension of segregation, they answer a different question from evenness measures like the dissimilarity index: not how unevenly groups are distributed, but how much members of one group actually share neighbourhoods with members of another or only with their own. The interaction index gauges cross-group exposure while the isolation index gauges within-group concentration, each interpretable as a probability.