Why Use a Cohort Approach to Analyse Internal Migration Trajectories?

Period and cohort approaches provide complementary insights into demographic behaviour and often proceed in tandem in fertility and mortality research. Yet, existing evidence on migration trends and patterns is, for the most part, based on period indicators applied to cross-sectional data, which cannot be disaggregated by move order. This chapter attributes the lack of progress in cohort migration analysis to data availability and argues that recent improvements in data collection practice open up new avenues for a cohort approach to migration. Following a brief review of previous studies, the chapter outlines the strengths and limitations of period and cohort approaches to examine migration trajectories. It details how differences in the conceptualisation of time are reflected in the type of data required, methods of analysis and research applications. The chapter goes on to describe tempo effects and their relevance to migration. It then argues for the importance of disaggregating migration by move order as an essential foundation to robustly identify variations between countries and over time in the timing of migration. The chapter concludes that both period and cohort approaches have their place in migration research and scholars should carefully weigh the advantages and limitations of each when seeking to address a particular research problem. By capturing the migration experience of individuals born in the same period as they progress through life, the cohort perspective is better suited to understanding how individuals transition from one migration to the next over their life course.