Select Committee on Treasury Eleventh Report

6  Improving current statistics

Recognising the need for change

107. In 2003, the ONS reported that a number of factors had developed since the 1970s that reduced the effectiveness of traditional methods used to obtain population estimates and supported an increased use of existing alternative sources used for counting the population of the UK and understanding its characteristics. These factors were:

108. Professor Coleman argued that "all aspects of population statistics in the United Kingdom are in an unsatisfactory state. Even the base population remains uncertain". [130] Professor Martin argued that in growth areas, current annual population estimates failed to anticipate or keep pace with the additional demands on resources resulting from a growing population. He noted that "there are particular weaknesses associated with all types of migrant populations".[131]

Inter-Departmental Task Force on Migration Statistics

109. In May 2006 the ONS established an Inter-Departmental Task Force on Migration Statistics with other government departments. The objective of the task force was to recommend timely improvements that could be made to estimates of migration and migrant populations in the United Kingdom, both nationally and at local level. The interim report of the task force was published in October 2007.[132]

110. The Inter-departmental Taskforce on Migration Statistics recognised the potential for improving statistics through using records from administrative sources. It recommended that access to a number of such sources was essential to develop record linkage approaches to measuring migration. Sources identified include components of the Work and Pensions Longitudinal Study (WPLS), migration statistics from new NHS IT systems, the School Census, and the Higher Education Statistics Agency (HESA). Taking forward the recommendations of the taskforce, ONS prioritised negotiating access to these sources. A framework for access was provided by the Statistics and Registration Services Act 2007. The Act contained powers to enable information sharing between public authorities and the newly established Statistics Board for statistical purposes. The powers are subject to the following safeguards:

  • protection of confidentiality;
  • only where there is no existing power/ it is otherwise prohibited by law;
  • subject to bilateral Ministerial agreement;
  • sharing only for specific purposes and subject to a public interest test and
  • Parliamentary approval.

111. The use of administrative records in combination would require the development of new tools and techniques, including the ability to evaluate the quality of the information for statistical purposes. The ONS told the Sub-Committee that projects specifically related to population statistics, Census and administrative data would be undertaken in 2008/9 to build on the work of the Taskforce.[133]

Estimating internal migration

112. The National Statistician told the Sub-Committee that the ONS was "confident about the national figures on the number of people entering and leaving the country", however she pointed out that they were "not nearly so clear about is where they actually go after they have arrived, where they settle, so we have already put in place an improvement in our latest population estimates using information from our household surveys, because from that we get a much better idea about where people are distributed around the country".[134]

113. The National Statistician told the Sub-Committee that the ONS had plans to continue improving the estimates, it had begun work with other government departments and Local Authorities to investigate "the use of administrative data which exists in central government, things such as the National Insurance Number register, the various registers that we have around children and schoolchildren".[135] However Professor Coleman argued that it was clear "that all these systems, never very effective, are now so unreliable that they have reached the end of the road of any effective radical improvement". [136]

Local Authority information

114. ONS reported that it had worked with Local Authorities to investigate local sources of information to assess whether they could be used on a nationally comparable basis to improve population estimates. Studies of four Local Authorities were conducted, each representing areas with specific issues in estimating population accurately. [137] The sources examined included:

  • The Electoral Register records people resident in each Local Authority who would be 18 or older during each year beginning 16 February and are eligible to vote in local government, devolved administration and or Parliamentary elections;
  • Housing Needs Surveys that are carried out by all Local Authorities in England; and
  • Council Tax Billing and Exemptions list based on a register of dwellings kept at the Valuation Office Agency. Each Local Authority is responsible for administering its own billing list.

115. ONS published reports on the individual studies earlier in 2007. [138] Workshops were held to discuss these reports, to which all Local Authorities were invited. ONS will shortly be publishing a final report on this work. [139]


116. National Insurance Number, Worker Registration System (WRS) and NHS Patient Registration data are commonly cited as alternative measures of population change. A comparison of these sources was published recently.[140] ONS is investigating how aggregate level counts from these and other alternative sources might be used in migration estimation and in producing additional indicators of population change at local level. The uses of and access to individual records is also being reviewed, following the recommendations of the Inter-Departmental Taskforce on Migration Statistics. Use of individual records from administrative sources would, in particular, make it possible to undertake linkage between information held on different sources. However, such data are potentially restricted and so are subject to limitations on access. [141]

117. Work has recently been undertaken within Departments, such as DWP, to investigate how existing linked data can be further exploited to improve the identification of migrant histories, including improved identification of emigration from the UK.[142]

E-Borders programme

118. The aim of the e-Borders programme is to transform the UK.'s border control to ensure greater security, effectiveness, and efficiency. It intends to use the "latest electronic technology" to provide a way of collecting and analysing information on everyone who travels to or from the United Kingdom. Other technologies, particularly biometrics, will ensure people can be identified securely and effectively.[143]

119. The UK Border Agency is responsible for delivering the e-Borders programme, and is doing so with the support of the police and HM Revenue & Customs. Information will be gathered on all travellers, passengers and crew entering or leaving the country by air, sea or rail.

120. The Home Office e-Borders programme aims to establish a modernised, intelligence-led border control. In the long-term e-Borders will provide the best option for recording individual movements into and out of the UK and length of stay in the UK for all modes of transport. However, it will only provide information about people arriving and leaving the UK not where in the UK they will live. In so far as it is possible to link journeys into the country with journeys out for the same individual, by identifying travel patterns it is in principle possible to separately identify long-term migrants, short-term migrants (including seasonal workers) and visitors. However detailed analysis will be required to develop rules for categorising people with more complex travel patterns, for example distinguishing those who take up residence in this country for a prolonged period but make frequent trips abroad from those who reside abroad but frequently visit the UK. [144]

121. The ONS is responsible for statistics on international and internal migration whereas the Home Office is responsible for statistics on immigration control. The ONS has been participating fully with the Home Office in the early stages of the e-Borders procurement process to ensure that full use can be made for analysis purposes of the extensive data that should start to become available from 2009. [145]

122. The Bank of England noted that there was a range of other data sources available on international migration which could be of use in the construction of population data. National Insurance Numbers issued and the Workers Registration Scheme data for A8 nationals are likely to be the most useful sources. Until the arrival of e-Borders there was no obvious replacement for the IPS as the main survey used to measure migration, but given the limitations of this survey already discussed other data sources could be used as a cross-check on the plausibility of IPS based migration data.

123. The Bank noted that the main problem with the alternative data sources is that they use different definitions of a migrant to that used in the mid-year population estimates and many can only be used to measure gross inflows rather than net migration. The ONS had already carried out a review of the potential to use these administrative data sources in population estimates. A publication to bring together and report in a coherent manner all the statistics collected across Government on migration and migrants is also planned. The ONS also plan a migration module, as an ad hoc addition to the LFS in 2008.

124. The ONS told the Sub-Committee that,

The e-Borders programme will create a joined up modernised intelligence-led border control and security framework. Enhanced information about passengers and their movements, and its communication through the use of new technology, processes and procedures will allow Immigration Service and other agencies including Police, Customs and Excise, Security Services to work more closely together to maintain the integrity of border control, target activity against those who have no right to be in the UK and assist in the fight against terrorists and criminals.

125. E-Borders will allow the ONS to introduce pre-boarding electronic checks of all persons flying to the UK, which will let us stop known security risks travelling. It will also collect information on when people arrive and whether they leave, which will help the Home Office to stop people staying in the UK when they have no right to. Bona fide travellers will also gain from faster clearance at points of entry.[146]

126. The Inter-departmental Task Force on Migration Statistics was established by the ONS in 2006 to undertake much needed research into the improvements that could be made to of estimates of migration within the United Kingdom. We expect the Statistics Authority to take this work forward.

129   ONS, Information paper: Census strategic development review Alternatives to a Census: Linkage of existing data sources, November 2003 Back

130   Ev 184 Back

131   Ev 24 Back

132   Ev 215 Back

133   Ev 214 Back

134   Q 193 Back

135   Q 194 Back

136   Ev 184 Back

137   Ev 212 Back

138   Improvements to Migration and Population Statistics- Update, National Statistics, Back

139   Ev 209  Back

140   Improvements to Migration and Population, National Statistics, Back

141   Ev 209-212 Back

142   House of Lords, Economic Affairs Committee, First Report of Session 2007-08,The Economic Impact of Immigration, HL 82-I Back

143   How e-borders works, Home Office, Back

144   Ev 213 Back

145   Ev 209-212 Back

146   How e-borders works, Home Office, Back

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