Why do we need migration data?
It’s an essential component of population change - If we want to estimate the size of the population now or in the future (project the population) we need to be able to estimate net migration.W
Which factors does migration affect?
- Population size
- Population structure (migration is often age and sex specific – and also selective by other characteristics e.g. health, skills)
- Population distribution (international migrants often enter in major towns and cities)
What is gross migration?
The sum of all migration between areas being considered.
What is net migration?
The difference between migration flows in both directions - this is often what we attempt to measure as it determines the impact on population size.
List two direct sources of migration data.
- Population registers
- Censuses
List an indirect source of migration data.
Administrative data such as NHS patient registers and Higher Education Statistics Agency data.
Write the formula for migration rate.
Migration rate = Number of people moving in period/
Population at risk of moving in period
