Friday 12 September 2003, 9:45am, Conference Centre
Judith Walton, Office for National Statistics (ONS)
Measuring population: the challenges and opportunities
The UK has traditionally used a census to obtain benchmark information about the population, and in the inter-censal period used the internationally recognised cohort component method to update population estimates. However, other countries have moved away from this model, or are considering doing so, instead using other approaches to collect census-type material. Indeed the ONS has announced that it is investigating alternatives to the traditional census.
The 2001 census has issued some challenges to those responsible for estimating population. After the release of the first census results, the National Statistician initiated a study into the uses made of population and household statistics, which could be used to inform decisions about how best to meet needs for population statistics in future. This study, 'A demographic statistics service for the 21st century', will be the catalyst for a range of improvements over the next decade. We face some major challenges in efforts to ensure that the range of statistics that describes the population and its characteristics remains relevant.
Although the overall population is relatively stable, there are some very significant changes in the make-up of the population and its behaviours. The population is becoming increasingly culturally diverse, it is ageing and more people have varied and increasingly complex living arrangements. Demographers need to measure these important changes.
Measures that have served well in the past may now have limitations. For example, the usually resident population definition places an individual at one address, and as such is unable to reflect some of the living arrangements that now exist. It has always been recognised that some groups in the population are more difficult to measure than others, but the balance and make-up of these groups is constantly evolving. Our data collection methods need to acknowledge this ongoing change if they are to provide the best possible information.
In meeting these challenges we will need to take advantage of a variety of new initiatives that might provide new ways in which to produce statistics or expand the range and quality of what is currently available. The project considering alternatives to a traditional census will research how increased use can be made of administrative data held both nationally and locally.
The Civil Registration Review offers an opportunity to change the range of statistics that are collected on births, deaths and marriages, which are presently defined in law. In the inter-censal period there is heavy reliance on surveys such as the General Household Survey (GHS) and Labour Force Survey (LFS) to provide information on families and households and on changes in the size of the ethnic community. These are high quality surveys but the sample sizes limit the extent to which statistics can be produced at regional and lower levels.
The ONS' work on the possibility of an Integrated Social Survey would provide core information for a much larger sample. The recent National Statistics Quality Review of International Migration Statistics has identified ways in which to improve the accuracy of the statistics on the most difficult component of population change to measure. Other projects are also underway to meet gaps in information needs, such as the Small Area Population Estimates Project. Finally, administrative initiatives may help us meet the challenges of measuring population. The Citizen's Information Project has been investigating the feasibility of building a UK population register to support a wide range of public services. Such a register would have statistical benefits.
These many and varied initiatives must be taken forward in a coherent manner, involving stakeholders to assist in defining requirements and determining priorities. Developing a programme of action from the 'A demographic statistics service for the 21st century' study will give us the focus required to improve population statistics over the next decade.
Judith Walton
Office for National Statistics
Segensworth Road
Titchfield
Fareham
Hants PO15 5RR
Email: Judith.Walton@ons.gov.uk