Inverse Projection
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.
Source record
Citations copied verbatim from the method’s source record. No claim-level verification is inferred from them.
- 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., Davies, R. S., Oeppen, J. E., & Schofield, R. S. (1997). English Population History from Family Reconstitution 1580-1837. Cambridge University Press. · ISBN 9780521590150
Curated claims
Claims persisted in the evidence ledger, each with its own assessment.
This view does not invent a claim assessment when the ledger has none.
Related methods
Generated from the method graph and shown as machine-suggested relations — no evidence claim is inferred.