Settlement Patterns and the Geographic Mobility of Recent Migrants to New Zealand
Appendix A: Labour Market Areas
Newell and Papps (2001) create labour market areas (LMAs) using travel-to-work data at area unit level drawn from the 1991 census. They define two sets of labour market areas - one with 140 areas and one with 58. The main differences are that the 140-area set provides greater disaggregation of some relatively small areas. We have chosen to use the more aggregated areas because of the small size of some of the additional splits and because our main estimator is estimated on an expanded analysis sample that is the number of individuals multiplied by the number of LMAs. Thus, computational limitations make it difficult to estimate this model with 140 LMAs.
The advantage of using functionally defined LMAs over administratively defined areas, such as territorial local authorities, is that migration between LMAs is generally associated with a change of job, whereas migration within a LMA is often motivated by residential factors. By disregarding migration within LMAs, we are able to largely isolate job-related migration. Administratively defined geographic areas are much less able to separate these two types of migration.