方法对比

	Rogers-Castro Migration Schedule	Net Migration Rate
领域	Migration Studies	人口学
方法族	Regression model	Process / pipeline
起源年份	1981	1976
提出者	Andrei Rogers & Luis J. Castro	Classical vital-statistics measure (formalized by Shryock & Siegel)
类型	Parametric curve-fitting model for age-specific migration rates	Rate of net population change due to migration per unit population
开创性文献	Rogers, A., & Castro, L. J. (1981). Model Migration Schedules. IIASA Research Report RR-81-30.	Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and Modeling Population Processes. Blackwell. ISBN: 9781557864512
别名	Model Migration Schedule, Rogers-Castro Curve, Multi-Exponential Migration Schedule, Age Profile of Migration	Net Migration Ratio, Crude Net Migration Rate, Net Migration per 1000
相关	3	4
摘要	The Rogers-Castro migration schedule is a parametric model that captures the remarkably regular way migration rates vary with age. Across countries and eras, the probability of moving is high in infancy, falls through childhood, surges to a sharp peak in the early adult labour-force years, and often shows a secondary bump around retirement. Andrei Rogers and Luis Castro, working at the International Institute for Applied Systems Analysis, formalized this regularity in their 1981 monograph as a sum of exponential and double-exponential curves whose parameters have direct demographic meaning. The simplest version uses seven parameters to describe the childhood decline and the labour-force peak; nine- and eleven-parameter extensions add retirement and post-retirement components. Fitting the schedule by nonlinear least squares smooths noisy age-specific rates, allows missing or sparse data to be filled in, and yields interpretable indices — the mean age of the labour-force peak, its sharpness, and the spacing between the childhood and labour curves. The result is a compact, comparable summary of an entire age profile of migration that feeds directly into multiregional projection and the analysis of migration selectivity.	The net migration rate expresses the net effect of migration on a population's size as a rate: net migration — in-migrants minus out-migrants over a period — divided by the population at risk, conventionally stated per 1000 people. It is the migration counterpart to the rate of natural increase and a standard component of population accounting. Because directional migration flows are often poorly recorded, net migration is frequently not counted directly but estimated as a residual from the demographic balancing equation or by comparing surviving cohorts across two censuses.