The implications of census 2021 data on Community Insight

By Thames Menteth-Wheelwright, Marketing Lead - on 27/07/2021

Although the census 2021 is complete, the ONS won’t be publishing outputs until March 2022 at the earliest. But when the data's finally released, here's what you can expect to see on Community Insight.

The first census release is likely to cover data on the total population at Local Authority level. This will then be followed by data on the major themes of the census, such as ethnicity, qualifications, economic activity, and general health. Following this we will see the release some of the small area data outputs – LSOA and MSOA.

The final release is likely to include datasets that cut across different themes. For example, you may be able look at datasets on age and homeownership or ethnicity and health in relationship to each other. Included too in this final release will be origin and destination data – an examination of travel to work patterns and migration patterns.

Our partners, OCSI, are intending to publish all statistical tables on Community Insight within one week of them being published by the ONS.

New Developments

The ONS is planning to develop a dissemination tool, which will allow users to create bespoke tables that cut across different sensor table themes. Users will be able to ask bespoke questions of the census, pertinent to their exact needs and combinations of data required, resulting in bespoke data tables for analysis. This is an exciting development which we hope to see applied to Community Insight.

New Geographies

Changes in Output Area geography:

  • Roughly 5% of Output Area (OAs) boundaries will change (2.5% changed in 2011)
  • Some LSOA and MSOA definitions will also change
  • All revised OAs will nestle into a stable hierarchy of Lower and Middle layer SOAs

As part of the Census 2021 update, the ONS are planning to make some changes to the Output Area geographies, with potentially up to 5% of all Output Area boundaries changing. This will have knock on effects for the LSOA and MSOA boundaries, as all areas will continue to nestle within larger boundaries. This is critical to Community Insight as Output Area boundaries are the building blocks for all the custom areas created by users.

There are three main circumstances where a change in OA boundaries may occur:

  1. Where the population has changed dramatically – a defining principle for OAs is that they are comparable in size and composition.
  2. To align Output Area boundaries more closely with the latest ward and parish boundaries to facilitate better data at these levels – so that fewer wards and parishes are based on ‘best-fit’ geographies.
  3. Where OAs are split by Local Authority boundary changes that have occurred since the 2011 Census, ensuring that they are aligned to the changed Local Authority boundaries as of 2022.

The pandemic may have resulted in unexpected changes to population as many people are not currently residing within what may have been their normal place of residence. For example, it’s estimated that a large number of people that are normally resident within the UK are currently living abroad, particularly foreign students and migrant workers, meaning we may see more changes in population patterns than were observed in the last census.

Impact on Community Insight functionality

To ensure that we are ready to load census data into Community Insight and that all the data in the system is based on the most up-to-date and relevant geographies, we propose to update Community Insight to run on Census 2021 OA/LSOA and MSOA geographies in advance of when the data for the Census 2021 is released at this geographical level. We will need to convert all custom areas built from component areas that have changed, so that they will be based on the new OA/LSOA/MSOA building blocks.

We will also need to ensure that we can continue to read in data for both new and old geographies, to support our users who hold their own data for old geographies, as well as for any data suppliers who are still publishing their data for old geographical boundaries. Where data is published for old geographies, we will convert it to the new geographies on the site.

Moving to the new Output Area boundaries will have some implications for users. Those custom areas which contain OAs, LSOAs or MSOAs that change in 2021 will be updated to reflect these changes. Users may therefore see some slight changes to the data for some of their custom areas.

For those areas created by standard area, users may see some changes to the way the boundaries on the map are displayed. Where change occurs, we will make sure that we notify any affected users of their custom area changes.

There will also be some minor changes to the thematic maps, with small changes to MSOA and LSOA boundaries. Because the number of areas will change, some areas may see a change in quintile rank where they were previously ranked on the margin of two quintile bands. However, this will be a small change that will only affect a handful of areas.

 

We will need to convert all older data to the new geographies and all new data published for old geographies, to align with the new boundaries, so there will be some small differences from the published data for data released for the old boundaries.

Lastly, any custom datasets users have uploaded may display differently and therefore may require re-uploading.

OCSI do not intend to implement any of these changes until the latter part of 2022, when the small area Census data is ready to load in.

Data Changes

The census 2021 will also bring updates to much of the data within Community Insight. This will see our largest single update to data we have ever managed as we expect to update up to 356 census indicators.

The new census population figures will have knock on effects for the Mid-Year population Estimates. As in 2011, the Mid Year Estimates will be revised to ensure they are aligned with the population base as counted in Census 2021 – this re-alignment will also affect the historical population estimates between Census 2011 and Census 2021. This will affect not only the population indicators themselves, but also any indicator which used population estimates as a denominator, with at least 275 indicators potentially affected.

New Data Opportunities and Discussions

As well as updates to existing indicators, there are likely to be new sources of interesting data from the census.

For example, there are new questions relating to sexual orientation and gender identity which will enable analysis of the size and socio-demographic characteristics of the LGBTQI+ communities in different local neighbourhoods.

ONS are also planning to develop a new flexible dissemination system for creating tables. This will make it easier to create bespoke tables which cut across multiple census themes, such as identifying areas with high concentrations of young adults with both low skills and high unemployment.

The new dissemination tool will also mean that the cross tabular data will be made available much earlier than it was last time around, when cross theme tables were some of the last outputs to be released. OCSI plan to engage with users closer to the time of release as to what sort of cross theme data users would like to see in Community Insight.

Another potentially exciting development is the possibility of linking census data with key administrative data at record level to produce multi-variate small area measures of interest.

The ONS consultation events so far indicate that they are having discussions with the Valuation Office Agency about producing a more sophisticated overcrowding measure that considers room size. They are also in discussion with HMRC and DWP about producing a robust small area household and personal income measure.

If you're interested in finding out more about Community Insight, get in touch with Lara Phelps for a demo and free trial.

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