The information requested falls within the responsibility of the National Statistician who has been asked to reply.
Letter from Karen Dunnell, dated 5 July 2006
As National Statistician, I have been asked to reply to your question about which local authorities according to the 2001 Census and the mid-2004 population estimates had a reduction in their populations. (81984)
The best comparison between 2001 and 2004 is based on the mid-year population estimates for those years, as the mid-2001 population estimates take account of adjustments to a number of areas as a result of the studies conducted after the Census. The attached table shows population estimates for those local authorities whose population decreased between mid-2001 and mid-2004.
Mid-2001 Mid-2004 Difference England North East Hartlepool UA 90,200 90,100 0 Middlesbrough UA 141,200 137,900 -3,300 Redcar and Cleveland UA 139,200 139,100 -100 Chester-le-Street 53,700 53,200 -500 Easington 94,000 92,900 -1,100 North Tyneside 192,000 190,700 -1,300 South Tyneside 152,800 151,500 -1,300 Sunderland 284,600 282,700 -1,900 North West Ellesmere Port and Neston 81,600 80,900 -700 Barrow-in-Furness 72,000 70,500 -1,500 Oldham 218,500 218,300 -200 Salford 217,000 216,400 -600 Stockport 284,600 282,200 -2,400 Burnley 89,500 88,100 -1,400 Knowsley 151,200 149,800 -1,400 St. Helens 176,800 176,700 -100 Sefton 282,900 281,800 -1,100 Wirral 315,000 313,100 -2,000 Yorkshire and the Humber Kingston upon Hull, City of UA 249,900 248,500 -1,400 North East Lincolnshire UA 158,000 157,700 -200 Erewash 110,100 110,000 -100 Corby 53,400 53,200 -200 Gedling 111,800 111,300 -600 West Midlands Stoke-on-Trent UA 240,400 238,000 -2,400 Shrewsbury and Atcham 95,900 95,800 -100 South Staffordshire 105,900 105,300 -700 Staffordshire Moorlands 94,600 94,300 -200 Tamworth 74,600 73,900 -700 Dudley 305,100 304,500 -600 Walsall 253,300 252,800 -500 East Luton UA 185,900 184,000 -1,900 Southend-on-Sea UA 160,400 159,600 -800 Harlow 78,800 77,500 -1,300 Broxbourne 87,200 86,100 -1,100 Hertsmere 94,500 93,300 -1,200 Stevenage 79,800 79,000 800 Watford 80,400 79,300 -1,100 London Hackney 207,200 207,000 -200 Lambeth 273,400 268,100 -5,300 Lewisham 254,300 247,000 -7,300 Newham 249,400 247,700 -1,700 Southwark 256,700 254,700 -2,100 Barking and Dagenham 165,700 164,600 -1,100 Brent 269,600 267,700 -1,900 Ealing 307,300 303,200 -4,100 Hounslow 216,000 212,300 -3,600 Sutton 181,500 177,600 -3,900 Waltham Forest 222,000 221,800 -200 South East Reading UA 144,700 144,000 -700 Slough UA 120,600 117,600 -3,000 Chiltern 89,200 89,100 -100 Wycombe 162,100 159,600 -2,400 Hastings 85,400 84,600 -800 Eastleigh 116,300 116,000 -300 Havant 116,900 115,700 -1,200 Rushmoor 90,900 88,800 -2,100 Gravesham 95,800 94,900 -900 South Oxfordshire 128,300 127,900 -400 Spelthorne 90,400 88,400 -2,000 Tandridge 79,300 79,300 -100 Woking 89,900 89,600 -300 Adur 59,700 59,300 -500 Crawley 100,400 98,700 -1,800 South West Bournemouth UA 163,600 163,500 0 Poole UA 138,400 137,000 -1,400 Wales Unitary Authorities Rhondda, Cynon, Taff 231,900 231,800 -100 Merthyr Tydfil 56,200 55,100 -1,100 Blaenau Gwent 70,000 68,800 -1,200 Torfaen 90,900 90,400 -500 Notes: 1. Figures have been rounded to the nearest 100 and therefore may not 'add'. 2. Where a difference of 0 is shown, the authority has reduced in size—but by an amount that rounds to zero. Source: Office for National Statistics.
The information requested falls within the responsibility of the National Statistician who has been asked to reply.
Letter from Karen Dunnell, dated 5 July 2006:
As National Statistician, I have been asked to reply to your question about what assessment has been made of the methods of collecting local authority population statistics. (81985)
The Office for National Statistics (ONS) liaises with users of population statistics across Government including the Department for Communities and Local Government (DCLG). The ONS provides advice to DCLG on the use of population statistics and on any issues raised by individual local authorities concerning the data and methodology used. Nevertheless, as an ONS product, any assessment of methods used in calculating population statistics remains a matter for the ONS. It is for this reason I have been asked to reply to your question originally addressed to the Secretary of State for Communities and Local Government.
The detailed methodology for population estimates is published here: http://www.statistics.gov.uk/StatBase/Product asp?vlnk=575
This methodology has been developed over a large number of years. Development of the methodology, together with the methodology for other population statistics, is done in conjunction with the Central Local information Partnership (CLiP) subgroup on population estimates.
The usually resident definition which formed the basis of the 2001 Census enumeration, and hence the mid-year estimates, was the result of extensive consultation with users and was reported in Census Advisory Group paper AG(99) 04 ‘Population Definitions for the 2001 Census’. A similar process is currently underway for the 2011 Census. For international migration, the population estimates use the United Nations definition of an international migrant (someone who migrates for a period of at least twelve months.)
The Cohort Component Method, which is the method used in the UK, is an internationally respected method used for estimating population estimates in a large number of countries. ONS is undertaking a study of the Cohort Component Method for the national population estimates, comparing the method used with those used in other countries. This is part of a larger project, Improving Migration and Population Statistics, about which I have written in more detail in other replies to you.
The information requested falls within the responsibility of the National Statistician who has been asked to reply.
Letter from Karen Dunnell, dated 5 July 2006:
As National Statistician I have been asked to reply to your recent question asking what steps are being taken to improve the collection of statistics on (a) internal and (b) international migration. (81986)
The Office for National Statistics (ONS) are currently carrying out an extensive programme of work titled Improving Migration and Population Statistics Project which is designed to investigate improvements to the population and migration statistics produced by ONS. Further information on this work can be found at: www.statistics.gov.uk/IMPS.
As part of this work, ONS is investigating how improvements may be made to estimates of internal migration which are currently produced using health records. In particular, the movement of students and young men are being considered and research is being carried out so that we have a better understanding of the movement of these and other mobile groups. We are also investigating other data sources that may inform our estimates of internal migration.
The programme of research described above is also taking forward recommendations from the National Statistics Quality Review (NSQR) into International Migration. The quality review made recommendations for improving the estimation of total migration flows to and from the UK and the allocation of international migration to local areas. This work includes investigating administrative sources that may be used in producing or quality assuring the international migration estimates, investigating potential sources of information about short-term migrants and making improvements to the current source of information on international migrants, the International Passenger Survey (IPS). The latest Progress Report on taking forward the recommendations of the NSQR on International Migration can be found at http://vrww.statistics.gov.uk/about/data/methodology/quality/reviews/population.asp
ONS are also conducting Local Authority case studies as part of the IMPS programme of work. These aim to get a better understanding, from a local perspective, of the administrative data sources that are currently used in the population estimation procedure. They will also investigate any other high quality sources that the local areas use themselves for population purposes.
The local areas selected for these studies are ones that are known to have reasons which make their population difficult to estimate, e.g. those with a high volume of migratory moves. It is intended that these studies will contribute towards the improvement of both internal and international migration statistics.
In May ONS set up a Task Force on Migration Statistics with other Government Departments, to identify improvements that could realistically be made over the next couple of years.
The information requested falls within the responsibility of the National Statistician who has been asked to reply.
Letter from Karen Dunnell, dated 5 July 2006:
As National Statistician, I have been asked to reply to your question about what assessment has been made of the accuracy of the mid-year population estimates. (81990)
Population estimates are calculated using an internationally respected methodology. Further information can be found in the detailed methodology guide 'Making a population estimate in England and Wales'. This is published here:
http://www.statistics.gov.uk/StatBase/Product.asp?vlnk=575
It is becoming increasingly difficult to estimate the size of the population because of changes in society, which include increased mobility and different living arrangements. Nevertheless, the mid-year population estimates remain the best available estimates of the population on a national basis. The decennial Census provides a benchmark against which national and sub-national population estimates can be assessed. Substantial work has been done on the difference between mid-year population estimates and the 2001 Census. This work is summarised in the final report of the 2004 Local Authority Population Studies, which can be found here:
http://www.statistics.gov.uk/downloads/theme_population/LAStudy_FullReport.pdf
Migration is acknowledged as the most difficult component of population change to estimate. My answer to your question about the steps being taken to ensure population estimates more closely reflect the effects of migration provides more detail.
In addition, extensive annual quality assurance is undertaken in order to ensure the accuracy of the annual mid-year estimates. Quality assurance starts with detailed checking of the source data used in the components of change (birth, deaths, etc.). Procedures are then in place to ensure that these data sources are correctly processed when deriving the estimates. the calculated national and sub-national estimates, for all 376 local authorities in England and Wales, are then subject to a further set of quality assurance procedures before they are published. These procedures include reviews of sex ratios and age profiles, comparisons of change over time, and comparisons of fertility and mortality rates. Substantial effort has already been undertaken, in recent years, to improve the quality assurance of population estimates.
The Office for National Statistics is also now investing substantially in a project to Improve Migration and Population Statistics (IMPS). (More information on this project can be found at: www.statistics.gov.uk/IMPS ) The key aims of this project are to reduce the size of the difference between the 2011 Census results and the mid-year estimates and to better understand any difference that does remain.
As part of this project, we are developing a data comparator tool to enable us to compare the annual mid-year estimates against a range of administrative sources. This work is ongoing and the results will inform our understanding of the accuracy of the mid-year population estimates. The tool was trialled in the mid-2004 population estimates, which were published in August 2005.
Another strand of the IMPS project is a review of the quality assurance procedures that are currently in place for population estimates. One of the aims of this review is to assess what improvements can be made to existing procedures, and determine whether additional quality assurance is required.
(2) when he will decide which further local authorities will join the improving migration and population statistics project.
The information requested falls within the responsibility of the National Statistician who has been asked to reply.
Letter from Karen Dunnell, dated 5 July 2006:
As National Statistician I have been asked to reply to your recent questions asking what criteria have been used to decide which local authorities were involved in the Improving Migration and Population Statistics (IMPS) project and when the Chancellor will decide which further local authorities will join the IMPS project (81991,81992).
Information was published on the method used for selecting local authorities for case studies on the NS website in March 2006. For more information see http://www.statistics.gov.uk/about/data/methodology/specific/population/future/imps/updates/defaultasp
Work is currently progressing on four local authorities. We are expected to report on the findings during the autumn. The outcome of the four case studies areas will then be evaluated. The selection and approach of any further case studies will be considered following the outcome of the review.
The information requested falls within the responsibility of the National Statistician who has been asked to reply.
Letter from Karen Dunnell, dated 5 July 2006:
As National Statistician I have been asked to reply to your question regarding what steps are being taken to ensure that the mid-year population estimates more closely reflect the effects of internal and international migration; and if the Chancellor will make a statement. (81993)
Migration is particularly difficult to estimate due to a rapidly changing population structure, which includes an increase in mobility and complex changes in living arrangements. ONS recognised this was a particular issue before the 2001| Census was undertaken.
The sources used to estimate internal migration were changed before the 2001 Census. Up to 1998 the National Health Service Central Register (NHSCR) was used in conjunction with data from electoral rolls. There were known limitations with the electoral roll data source. For example there were variations in the registers caused by the procedures used to maintain them. It was also possible for people to be registered in two different areas, such as students, and those under 18 were not included. Research was carried out that identified a higher quality data source in GP registers. From 1999 onwards, the internal migration component of the population estimates was based on a combination of NHSCR and GP register data.
Population estimates use the United Nations definition of an international migrant, which is somebody who migrates for a period of at least 12 months. Mid-year population estimates therefore estimate those that are ‘usually resident’ at that time. Following the 2001 Census a number of improvements were made to the methodology of international migration. Improvements were made to allow for those who stayed in their destination country for longer or shorter than they had originally intended, and therefore either became or were no longer considered a migrant (migrant and visitor switchers). Improvements were also made to fully allow for the migration of dependants of asylum seekers and to fully estimate outflows of failed asylum seekers and their dependants. Along with more minor technical adjustments to migration estimates, these changes have been incorporated into the revised 1991 to 2001 estimates.
The National Statistics Quality Review (NSQR) on International Migration was commissioned before the 2001 Census results were published. Please see the following link for further details of the NSQR:
http://www.statistics.gov.uk/about/data/methodology/quality/reviews/population.asp
Following publication of the 2001 Census the ‘Improving Migration and Population Estimates’ (IMPS) project was set up and incorporated recommendations of the NSQR. The IMPS project is primarily research based and concentrates on aspects of improving both internal and international migration and population statistics through methodology improvements and the identification of the most relevant and reliable data sources. The project is currently involved in liasing with a number of local authorities (LAs). ONS is working in partnership with these LAs to investigate whether local knowledge can help improve migration and population estimates. Any findings can potentially be applied to LAs with similar characteristics.
More specifically the IMPS project will consider how further improvements can be made to the internal migration methodology and data sources, one example of this is the issues around students registration with GPs. Research involving international migration will consider improvements in how to distribute International Passenger Survey (IPS) flows within England and Wales. In addition to this, other possible data sources will be considered, as will improvements to the estimations of IPS flows by altering and adding to existing questions in the IPS. In addition, ONS set up a Task Force on Migration Statistics in May. This aims to identify improvements that could realistically be made over the next couple of years.
We are also researching the feasibility of producing estimates of short-term migrants. The population estimates measure those that are usually resident and therefore do not measure those that are temporarily living in England or Wales. It is hoped that estimates of short-term migrants will be able to be used in conjunction with the existing population estimates.
Please find further details of the IMPS project here:
http://www.statistics.gov.uk/about/data/methodology/specific/population/future/imps/default.asp