Sammenlign metoder

	Inverse Projection	Aggregative Parish Register Analysis
Fagområde	Historical Demography	Historical Demography
Familie	Process / pipeline	Process / pipeline
Oprindelsesår	1981	1981
Ophavsperson	Ronald Lee; E. A. Wrigley and R. S. Schofield; generalized by Jim Oeppen	E. A. Wrigley and R. S. Schofield (Cambridge Group for the History of Population and Social Structure)
Type	Demographic reconstruction from aggregate flows	Time-series compilation and demographic indexing
Oprindelig kilde	Wrigley, E. A., & Schofield, R. S. (1981). The Population History of England 1541-1871: A Reconstruction. Edward Arnold / Harvard University Press. ISBN: 9780674690073	Wrigley, E. A., & Schofield, R. S. (1981). The Population History of England 1541-1871: A Reconstruction. Edward Arnold / Harvard University Press. ISBN: 9780674690073
Aliasser	Back projection, Generalized inverse projection, Demographic back-projection, Lee-Wrigley-Schofield projection	Parish register aggregation, Vital series analysis, Baptism-burial counting, Aggregative back-projection input
Relaterede	4	4
Resumé	Inverse projection, and its more flexible successor generalized inverse projection, reconstructs the demographic history of a population from the outside in. Where conventional cohort-component projection runs a known population forward using assumed rates, inverse projection runs the logic backward: starting from a population of known size and age structure at one date, and given annual totals of births and deaths, it infers the population sizes, age distributions, mortality levels, life expectancies and fertility rates that must have prevailed in earlier years. The technique was devised by Ronald Lee and applied by Wrigley and Schofield to their English aggregative series, allowing three centuries of population history to be recovered without any direct census before 1801. Jim Oeppen's generalization relaxed restrictive assumptions about migration and closed populations. The method is the bridge that turns raw counts of vital events into a fully articulated demographic regime.	Aggregative parish register analysis is the foundational technique of English historical demography, compiling the simple monthly and annual counts of baptisms, marriages and burials recorded in parish registers into continuous long-run series. Unlike family reconstitution, it does not identify individuals; it treats the registers as a barometer of the community's vital pulse. By assembling such counts from hundreds of parishes, Wrigley and Schofield built national series stretching back to 1538, the year English parochial registration began. From the relation between baptisms and burials one infers natural increase or decline; sharp spikes in burials betray mortality crises from famine or epidemic; the monthly distribution of events exposes the seasonality of marriage, conception and death. The method is comparatively economical, scalable across many parishes, and supplies the raw input series that inverse projection later transforms into full reconstructions of population size and structure.