Compare methods

	Geodemographic Classification	Index of Dissimilarity
Field	Human Geography	Sociology
Family	Process / pipeline	Process / pipeline
Year of origin	2005	1955
Originator	Richard Webber (and the geodemographics tradition synthesized by Harris, Sleight & Webber)	Otis Dudley Duncan & Beverly Duncan
Type	Pipeline that clusters small areas into interpretable neighbourhood types	Index of evenness of two groups across units
Seminal source	Harris, R., Sleight, P., & Webber, R. (2005). Geodemographics, GIS and Neighbourhood Targeting. John Wiley & Sons, Chichester. ISBN: 9780470864135	Duncan, O. D., & Duncan, B. (1955). A methodological analysis of segregation indexes. American Sociological Review, 20(2), 210–217.
Aliases	Neighbourhood Classification, Area Classification, Geodemographic Segmentation, Neighbourhood Typology	dissimilarity index, Duncan index, D index, segregation index
Related	4	5
Summary	Geodemographic classification is the process of grouping small geographic areas into a set of distinctive neighbourhood types according to the demographic, socioeconomic, and housing characteristics of the people who live there. It rests on the principle that 'birds of a feather flock together' — that residents of a neighbourhood tend to resemble one another and differ from those elsewhere — and turns dozens of census variables into a single, interpretable label for every area. Commercial systems such as Mosaic and ACORN and open classifications such as the UK Output Area Classification are all built this way, and the approach was consolidated as a discipline by Harris, Sleight and Webber in 2005.	The index of dissimilarity, often called the Duncan segregation index, measures how unevenly two groups — such as two racial or occupational groups — are distributed across a set of units like neighborhoods, schools, or occupations. It ranges from 0, when both groups have identical distributions across units, to 1, when the units are completely segregated, and has the intuitive interpretation of the share of one group that would have to relocate to achieve an even distribution.