Correction of age-specific migration data for mortality risk: methodology and application.

Type Working Paper - Demography India
Title Correction of age-specific migration data for mortality risk: methodology and application.
Volume 17
Issue 1
Publication (Day/Month/Year) 1988
Page numbers 96-108
Using data from the Indian Census of 1971, this paper adjusts migration data for mortality risk. The authors define the age specific migration rate as the ratio of the number of migrants age X at the time of migration, during a given year to the mid-year population of age X in the sending area. The assumptions involved in this method are 1) migrants depart uniformly during an interval of time so that together they experience the mortality of the destination area for 1/2 the period, on average; 2) among the survivors of migrants in each age group enumerated in the census, the ages at arrival of 1/2 of them would have been in the previous age group and of the remaining 1/2 in the same age group; and 3) migrants would experience the general mortality rates in the place of destination. Results of applying the method to interzonal migration data from the 1971 census shows that the out-migration rate decreases from age group (0-4) to (5-9), increases in the young adult ages, and gradually declines with only a slight increase in the old ages. This differs from the unadjusted out-migration rates which increase in the age group (5-9), remain constant until (10-14), reaches their peak in the age group (20-24), and decrease gradually. Corrections for mortality risk effect increases the zone from 7.82% in the Central zone to 10% in the West Zone. For Smaller areal units (such as state or district), the differences between the corrected and uncorrected migration rates would be more pronounced. Therefore, it would be worthwhile to make such corrections by age before using the out-migration rates for other purposes such as constructing multiregional life tables, projecting regional populations, and studying the spatial distribution of the country's population.

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