International migration and air travel: global smoothing and estimation

摘要

The relative likelihood of a migration from any one point on the earth's (land) surface to any other point is viewed as a function of four variables: the latitudes and longitudes of the origin and destination. It is expressed as a sum of six bivariate functions, one for each pairing of the four variables. Two of the six, attractivity and emissivity terms, are fitted by bicubic splines over a sphere (the earth), and the other four by bicubic splines over rectangular grids. The model is estimated with UN data on immigration streams from 169 nations to a subset of 93. A missing value procedure is implemented. National differences in definitions of immigrants are exposed through the examination of residuals. 1982 international air travel is modelled, as well. Exceptionally large passenger volumes are associated with pilgrimages to Mecca. Estimates of air traffic over potential or nonreported (confidential) routes can be obtained.