ABSTRACT
This chapter discusses comparative analyses and measures of migration. It presents an overview of how migration is defined and measured across the demographic surveillance sites. Migration is ideally measured as an event where every move made by an individual across a migration defining boundary is recorded at the time the move is made. The chapter describes the data collection methods and highlights the strengths and weaknesses of the data being collected by the Health Demographic Surveillance System sites (HDSS). HDSS are well-established features of the health and demographic data collection scene. The key features of a demographic surveillance system include a baseline census of a geographically defined population and mechanisms for continuously monitoring births, deaths and changes in residential status. The demographic surveillance systems were set up in most sites to provide sampling frames for public health interventions. The demographic surveillance system is an intensive longitudinal data collection and processing machine.
