ABSTRACT
This chapter makes the case for international comparative research on internal migration and goes on to highlight some of the methodological problems faced in doing this. These include different temporal coverages of national internal migration data series, different migration definitions (as events or transitions), varying population coverage and changes in the size and shape of the spatial units between which people are counted as moving. It then considers the various ways of overcoming these problems. These include creating consistent geographical units, modelling missing data and creating and using robust migration measures. It is argued that internal migration data should be collected that is consistent through time (and between countries) and that address-changing over a defined period is a good measure.
