I have been asked to reply.
The information requested falls within the responsibility of the UK Statistics Authority. I have asked the authority to reply.
Letter from Karen Dunnell, dated 22 May 2008:
As National Statistician, I have been asked to reply to your question on plans to increase the size of the sample in the International Passenger Survey. (206839)
The International Passenger Survey (IPS) is a multi-purpose survey which collects information from a quarter of a million passengers each year, as they enter or leave the UK. It is used for balance of payments, tourism and migration statistics. ONS has focused on whether the size of the migrant sub-sample is adequate.
Less than 1% of all travellers are long-term international migrants and the migrant sub-sample is much smaller than the total number of IPS interviews. In order to boost the size of the migrant sub-sample, additional sampling is conducted at selected ports. The 2006 inter-departmental Task Force into migration statistics included recommendations to improve the coverage of migrants in a port survey, particularly of emigrants. The number of emigrants sampled was increased with immediate effect, from 2007. ONS also immediately undertook a Port Survey Review (PSR) to investigate options for taking forward these particular recommendations.
An interim report of the PSR was published in October 2007 and is available on the National Statistics website:
A primary aim in the short-term is to deliver better migration data from a redesigned port survey while continuing to meet other statistical requirements. With this aim in mind, steps have been taken to increase the sample size from April 2008 by implementing new migration sampling at Manchester, Stansted and Luton and by introducing new IPS samples, or adding to existing samples at several other regional airports.
In the longer-term ONS is looking at more radical options for redesigning the port survey. It is expected that the number of migrant interviews on which estimates are based will be increased in a redesigned port survey.
A progress report on the PSR, to be published in the summer, will provide further details.