Estimation of period-specific gross migration flows from limited data: Bi-proportional adjustment approach

Two models, hierarchical in terms of input data requirements, are proposed to estimate place-to-place gross migration flows during a specified time period. In the first, the input data required are lifetime migration flows and the marginal totals of period migration, usually available from national censuses. The estimational algorithm is a ‘bi-proportional adjustment’ technique (and its variant) that assumes structural similarity between lifetime and period migration flows. The second model is designed to account for possible structural deviations in recent migratory patterns. Calibration of the procedure to replicate Indian and Korean data confirms high validity of estimation.