Survival Analysis of First Migration

Survival analysis of first migration treats the move out of one's place of origin as a timed event and asks not whether but when a person first migrates. Rather than modeling a binary 'migrated or not' outcome, it follows individuals from the moment they become at risk and models the instantaneous hazard of a first move as a function of age and changing life circumstances. The approach, codified for the social sciences by Blossfeld and Rohwer's event-history framework and applied to migration biographies by Clara Mulder, handles the two features that defeat ordinary regression: censoring, because most people in a sample have not yet migrated when observed, and time-varying covariates, because the things that trigger a move — finishing school, finding a job, forming a union — themselves change over time. The result is an estimate of how the risk of a first move rises and falls across the life course and how it responds to time-dependent conditions. It can be fitted nonparametrically with a Cox model or with a parametric baseline when the shape of age dependence is of interest.