Net long-term migration

You asked

The latest ONS figures estimate that net long-term migration to the UK (immigration less emigration) is 318,000 in the calendar year 2014. As the ONS base their estimates on the International Passenger Survey (IPS), a voluntary sample survey of passengers travelling via Britain’s main airports, sea routes and the Channel Tunnel which does not cover all ports of entry should this not be termed a guesstimate completely without statistical merit? As ONS figures exclude asylum seekers and their dependants and as the entire sample survey involves less than 800 interviews with a wide margin of error in what way is this report an accurate representation of physical numbers of migrants arriving in Britain? As the survey of those leaving does not cross reference their stated intentions i.e. to emigrate, with their actual practice i.e. how many return after emigration, of what use is the survey at all?

We said

Thank you for contacting the Office for National Statistics (ONS) regarding your concerns on the sources and methodology behind official estimates of long-term international migration for the UK. The response can be found within the attached document.