方法对比

	Net Migration Rate	Population Pyramid Analysis
领域	人口学	人口学
方法族	Process / pipeline	Process / pipeline
起源年份	1976	1874
提出者	Classical vital-statistics measure (formalized by Shryock & Siegel)	Francis A. Walker (early age-sex diagrams); standard demographic practice
类型	Rate of net population change due to migration per unit population	Graphical and tabular analysis of population age-sex structure
开创性文献	Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and Modeling Population Processes. Blackwell. ISBN: 9781557864512	Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and Modeling Population Processes. Blackwell. ISBN: 9781557864512
别名	Net Migration Ratio, Crude Net Migration Rate, Net Migration per 1000	Age-sex pyramid, Population age structure diagram, Age structure analysis, Nüfus Piramidi Analizi
相关	4	4
摘要	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.	Population pyramid analysis is the description and interpretation of a population's age-sex structure through a back-to-back horizontal bar chart, with males on one side, females on the other, and age groups stacked from youngest at the bottom to oldest at the top. The shape of the pyramid encodes a population's fertility, mortality, and migration history and is the demographer's first diagnostic of whether a population is young and growing, ageing, or contracting.