Applying model migration schedules to represent age-specific migration flows

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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
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Outline

• 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

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Research question and significance

• Question
• 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

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The Rogers-Castro (standard) multi-exponential
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. 1981a. Model migration
schedules. RR-81-30, International Institute for
Applied Systems Analysis, Laxenburg, Austria.
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The four main families of multiexponential model
migration schedules
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Age profiles of U.S. interstate migration and
immigration, 1985-1990
Aim develop a method for obtaining estimates of
age-specific migration flows given various levels
of incompleteness in the data Key assumption
aggregate migration levels are known
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Model migration schedule of observed age profiles
of migration in the U.S. West, 1985-1990
196 age profiles
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The four age profiles of interstate migration in
the U.S. West, 1985-1990
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Model migration schedules of observed standard,
young standard, old standard, and elderly
retirement age profiles of migration in the U.S.
West, 1985-1990
118 age profiles
34 age profiles
35 age profiles
9 age profiles
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Model migration schedules (standardized to unit
area) of observed age profiles of migration in
the U.S. West, 1985-1990
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Comparison of different age-specific models used
to predict age profiles of interstate migration
in the U.S. West, 1985-1990
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Comparison of different age-specific models used
to predict age profiles of migration from
California to Arizona, Colorado, Montana, and
Utah, 1985-1990
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The observed and predicted migration flows from
California to Arizona, 1985-1990
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The observed and predicted migration flows from
California to Colorado, 1985-1990
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The observed and predicted migration flows from
California to Montana, 1985-1990
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The observed and predicted migration flows from
California to Utah, 1985-1990
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Summary and discussion

• Four age profiles of migration were used to
  represent 196 flows
• Can extensions can be made to other contexts?
• 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