This unique book introduces an essential element in applied demographic analysis: a tool-kit for describing, smoothing, repairing and - in instances of totally missing data - inferring directional migration flows. Migration rates combine with fertility and mortality rates to shape the evolution of human populations. Demographers have found that all three generally exhibit persistent regularities in their age and spatial patterns, when changing levels are controlled for. Drawing on statistical descriptions of such regularities, it is often possible to improve the quality of the available data by smoothing irregular data, imposing the structures of borrowed and related data on unreliable data, and estimating missing data by indirect methods. Model migration schedules and log-linear models are presented as powerful methods for helping population researchers, historical demographers, geographers, and migration analysts work with the data available to them.

Résumé
This book presents the culmination of our collaborative research, going back over 15 years (Rogers & Little, 1994), and for one of us, even longer (Rogers, 1967, 1973). It addresses a dif?cult, yet necessary, area of demographic research: what to do in data situations characterized by irregular, inadequate, or missing data. A common solution within the demographic community has been what is generally referred to as indirect estimation. In our work the focus has been on the indirect estimation of migration, and our use of the term indirect follows the description given in the 1983 United Nations manual, which de?ned it as techniques suited for analysis of incomplete or defective demographic data (United Nations, 1983, p. 1). We wrote this book with a goal to make it accessible to a reader familiar with introductory statistical modeling, at the level of regression and categorical data an- ysis using log linear models. It is primarily intended to serve as a reference work for demographers, sociologists, geographers, economists, and regional planners.

Contenu
Describing Age Structures of Migration.- Describing Spatial Structures of Migration.- Smoothing Age and Spatial Patterns.- Imposing Age and Spatial Patterns.- Inferring Age and Spatial Patterns.- Conclusion.