When is a move a migration?

It is demonstrated that the two forms of mobility are behaviorally distinct, and workplace and residence relocations tend to be 'substitutes' in intra-regional mobility but are 'complements' in inter-Regional mobility.

Abstract

"This paper extends the traditional theory of urban location to derive a consistent model of inter- and intra-regional mobility. It demonstrates that the two are behaviorally distinct. Workplace and residence relocations tend to be 'substitutes' in intra-regional mobility but are 'complements' in inter-regional mobility. Previous empirical papers have neglected the theoretical foundations of intra-regional mobility. In consequence, they have made four types of analytical compromises: defined 'migration' as any change in residence location, used job changes as proxies for workplace mobility, neglected commuting distances, and used estimation techniques that do not reveal the underlying behavior."