Compare methods

	Vacancy Chain Analysis	Rank-Size Rule
Field	Human Geography	Human Geography
Family	Process / pipeline	Process / pipeline
Year of origin	1970	1949
Originator	Harrison C. White	George Kingsley Zipf
Type	System model of mobility driven by the movement of vacancies through linked units	Empirical regularity and diagnostic for the size distribution of cities
Seminal source	White, H. C. (1970). Chains of Opportunity: System Models of Mobility in Organizations. Harvard University Press, Cambridge, MA. ISBN: 9780674080652	Zipf, G. K. (1949). Human Behavior and the Principle of Least Effort. Addison-Wesley, Cambridge, MA. ISBN: 9781614273790
Aliases	Vacancy Chain Model, Chains of Opportunity, Vacancy Transfer Analysis, Vacancy Chain Mobility Model	Zipf's Law for Cities, Rank-Size Distribution, City-Size Rank-Size Relationship, Rank-Size Regularity
Related	4	4
Summary	Vacancy chain analysis is a system model of mobility, introduced by Harrison White in his 1970 book Chains of Opportunity, that follows opportunities rather than people. When a unit such as a house or a job is freed and filled by someone who in turn vacates another unit, a chain of moves cascades through the system until it ends with a new entrant or a unit leaving the stock. By treating vacancies as the things that move — through an absorbing Markov chain — the framework explains how a single new dwelling or retirement can ripple into many household relocations or promotions.	The rank-size rule is an empirical regularity describing the size distribution of cities within a country or region. In its simplest form, popularized by George Kingsley Zipf in 1949, the population of a city is inversely proportional to its rank, so the second-largest city is about half the size of the largest, the third about a third, and so on. Generalized to a power law with an exponent q, it provides a compact way to summarize how evenly or unevenly population is spread across a settlement system and to diagnose urban primacy.