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Please explain how you currently use ONS population and migration statistics? 

We are responding on behalf of, and following consultation with, our members. These include researchers and professionals from national and local government, academia and the private sector who use these data in a wide of contexts. Many have been involved in the development and use of
administrative data. Our comments are general.

To what extent do these proposals meet your needs?

The proposals meet some of my needs

Are your current information needs better met by these proposals?


Which of your current needs would not be met by these proposals? Please include reasons for your answer. For example, information around levels of
detail, accuracy, timeliness or geography.

Surveys will not provide us with reliable neighbourhood-level information – for example to identify sub-district inequalities between ethnic groups. This
will be a problem for academic researchers, but also for Local Authority analysts, etc.


Do the proposed levels of geographic breakdown meet your information needs?


What additional geographic breakdowns would you need? 



What impact would this change in available detail have on your use of our population and migration statistics? Please explain your answer.

Population definitions and estimates

Is there anything else about the population and migration statistics proposal that you wish to add to your response?

We agree with the consultation that progress has been made towards counting the population with administrative data using the Dynamic Population Model. However, much less progress has been made towards replacing the other roles played by the census including the provision of small area social, economic and housing statistics. The proposals bring benefits in terms of data timeliness but represent serious constraints in terms of detail, accuracy and geography.


The key concerns of the community are:

  1. Scale: The “baseline objective” in the proposal is to deliver annual statistics at the local authority level for all topics covered by the census. This does not meet user needs because: (i) a key role of the census is to deliver statistics for small areas within local authorities (the proposal guarantees this for only a subset of topics); (ii) delivering this full range of statistics requires an ongoing role for social surveys, but this role has not been specified; (iii) the precision of the outputs cannot be predicted. Following the Beyond 2011 decision it was envisaged that there would be parallel administrative-based outputs to compare to the traditional census. Whilst some administrative-based research outputs have been published, the quality of many important outputs from the proposed system are unknown. The community also raised questions about what measures will be in place / what is the confidence in a representative approach across all types of LA’s and characteristics of interest? Who will be under-represented by the proposed approach?
  2. Evolution: The decennial census has a central role in the national statistics system that is much wider than its direct outputs. The census offers a regular cycle on which to reconsider data collection, adding new questions and refining others (e.g. the evolution of the question on ethnicity). How these functions would be fulfilled by the proposed population statistics system is not fully described in the consultation.
  3.  Access: We have concerns over the robustness of access to and control over administrative data. To deliver quality official statistics, users expect that ONS can exert control over the data collection process. This would include the right and the means to access central government data on an agreed timetable, an influence over what data is collected (such that new data could be collected), control over the quality of that data and a robust system for cross-departmental data linkage. The legislative, technological and managerial systems are not in place to deliver this, which puts the proposed administrative-based system on a fragile footing. This is a particular concern across the devolved nations.
  4. Longitudinal data: The proposal to replace the longitudinal and historical outputs of the census is underdeveloped. Aspirations to fully replace these outputs are included in the consultation document but require more detail to assure users.
  5. Cost: The consultation document estimates that the proposed new system would “cost less than half the cost of a 2031 census over a ten-year period”. Yet key aspects of the system are unspecified, so it is unclear on what basis this estimate has been made. The costs and benefits of proposed new system cannot be comprehensively evaluated as the system has not yet been fully designed. From a user point of view, we are concerned that the system will be designed to fit the budget, leaving key statistical outputs vulnerable to underfunding.
  6. Trust: The vast majority of UK residents take part in the census. With each census media interest peaks and the nation engages with current local and national population issues and concerns. Social surveys, in contrast, are experiencing a collapse in response rates globally and relying on them presents significant risks. The system relies upon public acceptability of administrative data linkage and opt out mechanisms, both currently and in the future. Associated trust issues were also raised with regard to the reuse of data. How are ethical questions of reuse being taken into account, and how will this be explained to the public?
  7. The community would suggest that medium-term future of population and migration statistics continue to require a decennial census alongside the further development of administrative data sources and methods and, critically, the linking and sharing of these data sets. The proposal is not sufficient to meet user needs for quality population, migration, social, economic and housing statistics in time to replace a census in 2031.

Read the consultation response