isolation index

Isolation index measures the degree to which people inhabit geographic units inhabited primarily by members of their own group. It is usually denoted by I. It varies from 0 to 1.0 and is defined as the proportion of own-group members in the unit of the average person. In measuring black isolation, for example, a score of 1.0 means that the average black person lives in a neighborhood that is 100 percent black, and a score approaching 0 means that this person lives in a neighborhood where he or she is nearly the only black resident.{{Cite journal |last1=Massey |first1=Douglas S. |last2=Denton |first2=Nancy A. |date=December 1988 |title=The Dimensions of Residential Segregation |url=https://doi.org/10.2307/2579183 |journal=Social Forces |volume=67 |issue=2 |pages=281 |doi=10.2307/2579183 |jstor=2579183 |issn=0037-7732|url-access=subscription }} They have been used in studies of racial segregation{{cite web|url=http://enceladus.isr.umich.edu/race/calculate.html|publisher=Population Studies Center, University of Michigan|title=SexRacial Residential Segregation Measurement Project|access-date=2010-12-06|archive-date=2011-05-17|archive-url=https://web.archive.org/web/20110517151422/http://enceladus.isr.umich.edu/race/calculate.html|url-status=dead}} and ideological segregation.{{cite web|title=Escape From the Echo Chamber|publisher=Slate magazine|author1=Chadwick Matlin |author2=Jeremy Singer-Vine |author3=Chris Wilson |date=April 29, 2010|url=http://www.slate.com/id/2252247/}}{{cite journal|title=Ideological Segregation Online and Offline|author1=Matthew Gentzkow |author2=Jesse M. Shapiro |journal=Quarterly Journal of Economics|url=https://academic.oup.com/qje/article/126/4/1799/1924154|date=3 November 2011|volume=126 |issue=4 |pages=1799–1839 |doi=10.1093/qje/qjr044 |hdl=1811/52901 |hdl-access=free }} Isolation index is not invariant to relative size of group.

Examples of isolation indices include Lieberson's isolation index and Bell's isolation index.{{Cite journal | last1 = Robinson | first1 = V. | title = Lieberson's Isolation Index; A Case Study Evaluation | jstor = 20001630 | journal = Area | volume = 12 | issue = 4 | pages = 307–312 | year = 1980 }}