Compare methods

	Nearest Neighbour Index	Central Place Analysis
Field	Human Geography	Human Geography
Family	Process / pipeline	Process / pipeline
Year of origin	1954	1933
Originator	Philip J. Clark & Francis C. Evans	Walter Christaller
Type	Summary statistic for the degree of clustering or dispersion in a point pattern	Theory and analytic framework for the size, number, and spacing of settlements
Seminal source	Clark, P. J., & Evans, F. C. (1954). Distance to nearest neighbor as a measure of spatial relationships in populations. Ecology, 35(4), 445–453.	Christaller, W. (1966). Central Places in Southern Germany (C. W. Baskin, Trans.). Prentice-Hall. (Original work published 1933). ISBN: 9780131226302
Aliases	Clark-Evans Index, Nearest Neighbour Analysis, NNI	Central Place Theory, Christaller Central Place Model, Settlement Hierarchy Analysis, Central Place Hierarchy
Related	4	4
Summary	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.	Central place analysis is the study of the size, number, and spacing of settlements as service centres, grounded in Walter Christaller's central place theory of 1933. It explains why settlements form an orderly hierarchy — many small villages, fewer towns, a handful of cities — and why higher-order centres are spaced farther apart and offer more specialized goods, deriving the famous nested pattern of hexagonal market areas from two economic concepts: the range and the threshold of a good.