Stepwise Migration Analysis

You need the full sequence of a migrant's residences, not just origin and current home. Rank each place on a settlement hierarchy and trace the path: a stepwise pattern climbs one rung at a time, village to town to city, while a direct move jumps across rungs in a single transition. The crucial point Conway made is that you cannot infer stepwise migration from a snapshot — many rural-born people in a city may have moved there directly. Only the reconstructed trajectory distinguishes a staged ascent from a leapfrog.

Because 'step' is meaningful only relative to a ladder of places. How you rank settlements — how many tiers, where the boundaries fall, whether you use population size, functional centrality, or both — determines whether a given move counts as a single-rung step or a multi-rung jump. The same migration histories can look predominantly stepwise under a fine hierarchy and predominantly direct under a coarse one. That is why the hierarchy must be constructed explicitly and justified, and why sensitivity to alternative rankings should be checked.

A stepping stone is a place that equips migrants to move further up the hierarchy. Drawing on the mechanisms synthesized by Massey and colleagues, an intermediate town can supply information about larger cities, social-network contacts who ease the next move, and the earnings, skills, and urban experience that make it feasible. Stepwise analysis goes beyond describing sequences to testing whether such places actually perform this enabling function — that is, whether time spent there raises the probability of a subsequent upward move rather than simply being a final destination.