We revisit the modelling of gross inter-urban migration flows in New Zealand. As in previous work, we identify a range of geographic, demographic, economic and climatic characteristics of urban areas, which are statistically significant determinants of migration. However, we argue that in a small but open population such as New Zealand (in which one quarter of the resident population is foreign born and one sixth of the New Zealand-born population lives abroad), inter-urban migration should be modelled jointly with rural-urban and international migration.
We proceed to estimate a modified gravity model of migration in which the flow matrix is augmented with rural-urban and international migration. Migration data are obtained from four successive population censuses since 1996. We find notable differences in the impact of migration determinants when comparing urban-urban, urban-rural and urban-world migration flows. The estimation of these models is straightforward and does not require collection of data on rural areas or foreign countries. Hence, the method can be easily applied to other case studies in which international and/or rural-urban migration are important components of population churn.
Alimi, Omoniyi & Maré, David & Poot, Jacques. (2019). Modelling Inter-urban Migration in an Open Population Setting: The Case of New Zealand. DOI: 10.1007/978-981-13-9231-3_11 In book: Population, Place, and Spatial Interaction, pp.201-223.