ANNALES DE DÉMOGRAPHIE HISTORIQUE 1989 Société de Démographie Historique - E.H.E.S.S., Paris, 1989.
POPULATE®
A MICROCOMPUTER PROJECTION PACKAGE FOR AGGREGATIVE DATA APPLIED TO NORWAY, 1736-19701
par Robert McCAA
...sur le fond les méthodes de projection avant ou arrière obéissent aux mêmes principes (c'est en fait la logique de la dynamique des populations soumises aux mêmes contraintes).
Alain Blum and Noël Bonneuil2
Introduction
One of the most important methodological innovations in population history over the past two décades has been the development of aggregative techniques to compute age-specific démographie measures from simple counts of baptisms and burials. In the early 1970s, L. Henry, E. van de Walle, and others applied projection methods to richly detailed data for France to reconstruct national and departmental populations for the eighteenth and nineteenth centuries3. At about the same time, inverse and back projection techniques were developed to exploit data for England extending to the middle of the sixteenth century4. Thèse methods harness long séries of vital events to models of mortality, migration, and population âge structures to compute annual or quinquennial estimâtes of life expectancy and reproduction ratios as well as population by âge. Ail aggregative methods balance the démographie équation with counts of births and deaths. They differ in two ways : first, by their use of models to make up for the absence of age-specific data, and second, in the estimation of migration.
1. "Copyright R. McCaa and H. Perez Brignoli. Ail Rights Reserved. Populate was partially funded by Project Woksape, a collaborative undertaking between the University of Minnesota and the International Business Machines Corporation to promote instructional Computing. I wish to express spécial thanks to H. Perez Brignoli, R. Lee, S. Ruggles, A. Fauve-Chamoux, G. Alter, R. H. Jackson, and R. Jensen among others who offered valuable criticisms for improving the Populate microcomputer program, and to the anonymous reviewers of this journal for suggesting clarifications on several points.
2. A. Blum and N. Bonneuil, "Projections rétrospectives des populations du passé", Vin* Colloque National de Démographie, Les Projections Démographiques Actes du Colloque, Paris, 1987, 1 : 59.
3. Y. Blayo and L. Henry, "La population de la France de 1740 à 1860", Population, 7 Numéro Spécial, 1975, 71-122. E. Van de Walle, The Female Population of France in the Nineteenth Century, Princeton, NJ, 1974.
4. R. Lee, "Estimating Séries of Vital Rates and Age Structures from Baptisms and Burials : A New Technique with Applications to Pre-industrial England", Population Étudies, 28, 1974, 495- 512 ; and E. A. Wrigley and R. S. Schofield, The Population History of England, 1541-1871 : A Reconstruction, Cambridge, Mass., 1981. Lee questions whether back projection is a déterminant System of équations in "Inverse Projection and Back Projection : Comparative Results and Sensitivity Tests For England," Population Studies, 39, 1985, 233-248.
