Applying model migration schedules to represent agespecific migration

Applying model migration schedules to represent age-specific migration flows James Raymer University of Southampton Andrei Rogers University of Colorado Paper prepared for presentation at The Third International Population Geographies Conference, Liverpool, 19 -21 June 2006

Outline l l l Research question and significance The multiexponential model migration schedule Age-specific patterns of migration in the U. S. West Application of model migration schedules to represent age-specific migration flows Some results Summary and discussion

Research question and significance l Question – l How can known regularities of age-specific migration be better used to estimate migration flows? Significance – – Age-specific data are needed for planning and understanding patterns Often these data are incomplete or not available

The Rogers-Castro (standard) multiexponential model migration schedule Model schedules are used to: Identify regularities Smooth irregular data Infer missing data Represent unknown age profiles Rogers A and LJ Castro. 1981 a. Model migration schedules. RR-81 -30, International Institute for Applied Systems Analysis, Laxenburg, Austria.

The four main families of multiexponential model migration schedules

Age profiles of U. S. interstate migration and immigration, 1985 -1990 Aim: develop a method for obtaining estimates of agespecific migration flows given various levels of incompleteness in the data Key assumption: aggregate migration levels are known

196 age profiles Model migration schedule of observed age profiles of migration in the U. S. West, 1985 -1990

The four age profiles of interstate migration in the U. S. West, 1985 -1990

118 age profiles 34 age profiles 35 age profiles 9 age profiles Model migration schedules of observed standard, young standard, old standard, and elderly retirement age profiles of migration in the U. S. West, 1985 -1990

Model migration schedules (standardized to unit area) of observed age profiles of migration in the U. S. West, 1985 -1990

Comparison of different age-specific models used to predict age profiles of interstate migration in the U. S. West, 1985 -1990

Comparison of different age-specific models used to predict age profiles of migration from California to Arizona, Colorado, Montana, and Utah, 1985 -1990

The observed and predicted migration flows from California to Arizona, 1985 -1990

The observed and predicted migration flows from California to Colorado, 1985 -1990

The observed and predicted migration flows from California to Montana, 1985 -1990

The observed and predicted migration flows from California to Utah, 1985 -1990

Summary and discussion l l Four age profiles of migration were used to represent 196 flows Can extensions can be made to other contexts? – – – l Intercensal survey data International migration between countries in the EU Less developed nations Future work involves identifying key factors that explain different age profile shapes