With the Census in England and Wales taking place on 21 March 2021, we created a programme of webinars to showcase our plans for design and quality assurance. The series, which was carried out through November and December 2020, included a high-level introductory overview as well as 'In Focus' sessions that outlined specific aspects in more detail. These webinars gave attendees the opportunity to ask questions and provide feedback.
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Census 2021 Outputs
Welcome
Please turn off your camera and mute your microphone
Questions?
Visit www.sli.do and enter code 78579 to ask your questions
Technology problems?
Email sdr.stakeholder.engagement@ons.gov.uk
Starting at 10:45am
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Aims for this Session
• Share the lessons learnt from the 2011 Census, the 2018 Output
consultation and ongoing user research.
• Outline the proposed suite of Census 2021 outputs, products and services.
• Demonstrate how Census 2021 outputs and dissemination approaches will
be flexible, timely and accessible.
• Describe the methods for protecting confidentiality in Outputs
(statistical disclosure control).
• Consider how ONS and Census users can work together to assess the
impact of the coronavirus pandemic on using census outputs.
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Why are we running these webinars?
• To explain how the census works in collecting information
and producing great statistics.
• To sign-post where more information is available.
• To follow on from the material we published in October:
• COVID response
• Statistical Design
• Findings from 2019 rehearsal
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Census 2021 Quality Targets
High quality, flexible,
timely, accessible census
statistics for users
94% overall
response
At least 80% in
every local authority
75% Online
Response
Minimise variability
in response
Support
completion
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“The cost and effort of taking a census
is only worthwhile when the results are
provided to users in ways that they can
use the information to improve the
decisions they make…”
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Lessons from 2011
What went well
• 2011 Census outputs were the most
comprehensive to date.
• National Statistics accreditation went
smoothly.
• Technical support, statistical control,
and creation of products all went well.
What didn’t go so well, and lessons
• It took too long for all the outputs to be
released.
• Late changes to table specifications were
unwelcomed in terms of changes and
delays.
• Users wanted more flexibility to build tables
relevant to their area and characteristics.
• Not to overpromise and manage
expectations – both in terms of Outputs
and Systems to access them.
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2018 Output Consultation feedback
You told us:
• You support the strategy to disseminate census data using a flexible
dissemination system, and the associated statistical disclosure control approach.
This is for reasons of timeliness and flexibility.
• You would prefer a single point of access to census data, and options for
downloading large volumes of data.
• There is a clear need for data about income derived from administrative data
sources, especially at lower geographies to help users with analysis and service
delivery.
• There is an overwhelming need for timely and accessible origin-destination data.
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A new flexible, timely and accessible approach
to Census 2021 outputs
Flexible: A wider range of outputs to meet the needs of a greater
range of users. More control for users to create own outputs.
Timely: We aim to make outputs available sooner than for the 2011
Census.
Accessible: Available in ways that suit users needs, with supporting
information to enable understanding of the data.
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Comparison of Census outputs release: 2011 & 2021
Main area for improvement
compared to 2011
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Data Tables
• Bread and butter of Census Outputs.
• Produced since 1801.
• Single variable and cross-classifications of multiple variables.
• Historically constrained by the need to have tables that ‘work’
for all areas and to produce a set that best meets range of
different user needs.
• Are produced for a range of population bases (including the
usual resident population).
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Innovations for 2021
• Distinction of ‘ready-made’ tables along the lines of what
has traditionally been produced, with ability for users to
‘Build their Own’.
Data Tables
Ready
Made
Tables
Build Your
Own
Tables
Tables that
flex
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Ready made tables
• Similar in concept to those produced in 2011 and before.
• We’ll consult on them to agree table specifications.
• Current thinking is that we will propose a set based around the Local
Characteristic Tables, Key Statistics and Quick Statistics produced in 2011
(with additions and changes).
• The intention is that these tables would be made available for all geographic
areas at a particular level (i.e. ‘blanket’ coverage).
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Build Your Own Tables
• Users to request their own combinations of variables
to produce datasets that suit their particular needs.
• Likely to be similar classifications as those used in
Local and Detailed Characteristics tables in 2011.
• The tool builds tables very quickly and applies
disclosure control methods and checks automatically.
• Those checks determine the areas that the requested
table can be made available for– and tables for a
‘patchwork’ of areas can be produced.
• This capability is now fairly mature and we have
proven it as part of rehearsal activities.
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Tables that flex
• This is more conceptual and not yet proven or
developed.
• The concept enables users to ‘flex’ a ready-made
table (for example to be able to increase the level of
detail of a variable in that table).
• We are particularly keen on user feedback on this
concept.
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Statistical Disclosure Control
• In order to be able to offer greater flexibility whilst maintaining the confidentiality of the
information provided, we will have a multi-layered approach to disclosure control.
1. Targeted Record
Swapping
2. Cell Key Perturbation
3. Automated Disclosure
Checks
Uncertainty
Protects unique individuals
and households
Noise
Protects against
differencing
Checks
Protects against sparsity
and disclosures
• In combination, these methods enable the provision of flexible outputs and for them to be
provided more quickly than before. This enables the provision of data using a ‘patchwork’
approach, in areas where the data supports that level of detail.
• The ‘cost’ is that there are small differences in tables (inconsistent totals).
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‘Bespoke, restricted or commissioned’
Origin -
Destination
Building on 2011 products with
increased focus on public
accessible products, as well as
the more detailed data tables.
Small Population
Outputs e.g.
Cornish, Sikh
Building on set of tables produced
from the 2011 Census and keen to
engage with stakeholders to
understand needs and design suitable
products.
Microdata
samples
SRS and UKDS
Plans are similar to 2011 with the addition
of a safeguarded household microdata file
and provision in IPUMS format.
Commissioned
Outputs
Continuation of existing service for
commissioning of Census outputs not
already made publicly available.
Improved offering
Bespoke, restricted or commissioned
Standard
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Richer content
• Arguably, even more opportunities for providing more value to
existing and new users through new and innovative products.
• Exploring changes both in products that could be provided and
also how they can be created.
Richer Content (words, pictures, insights)
Analysis Area Profiles
Area
Classifications
Data
Visualisations
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Census Analysis Aims
The Census Analysis Co-ordination team at ONS is responsible for managing the delivery
of an analytical work programme for Census 2021 across all census topic areas. This will
include combining Census data with other data where useful. An analysis plan is being
developed that to define this work with the following aims:
• Helping users understand and interpret the census data
• Meet requirements of our diverse range of users and stakeholders
• Provide a springboard for analyses by other organisations
• Inform government policy and public debate
• Deliver new outputs and products, using innovative methods
• Utilise all available sources to fill analysis gaps for our users
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Geography
Have your say
Geography policy, products and services consultation – open until 18 Dec 2020
• Intend to continue the use of Output Areas (OAs) and to best-fit to other geographies.
• As with previous censuses looking to keep change to OAs to under 5%.
• Splits and merges where OAs now break thresholds on population
size for 2021.
• Use of Admin data to predict where this will occur, to speed up process.
• Potential for additional targeted re-alignment to create a better fit to some wards and
parishes.
• Continuation of existing products such as Travel to Work areas and Area Classifications.
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Metadata
Information to support the data
• Range of types, from definitions through to detailed Quality reports.
• Keen to identify metadata needs early in the census consultation process.
• Looking to ensure products are timely, comprehensive and easily accessible.
• Exploring the use a centralised metadata storage and management solution for key
metadata.
• Improve UK harmonisation of metadata.
• Metadata will need to support the range of potential census output and analysis
products.
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Accessing Data
• Work taking place within ONS to determine the dissemination capabilities
that will be in place for the release of the 2021 Census Outputs.
This is based on extensive user research.
• We are yet to make formal decisions on the exact nature of systems that
will be used to provide access to the 2021 Census Outputs. Work is
currently taking place to ensure that Nomis would be available and able to
provide 2021 Census data (including flexible tables) to users, if required.
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Value of the census greater than ever
• As a snapshot the census data will paint the picture of our society at significant
point in time.
• That point in time also means it can provide an important baseline for expected
changes ahead. For example the impacts and recovery from the Covid-19
pandemic, and other events and initiatives such as Brexit and ‘Levelling-up’.
• We expect that the rate of change for some topics is likely to be higher than
usual in the intercensal period e.g. employment and health.
• We want to make best possible information available to support decision-
making:
• we will be exploring how we can use other survey and administrative sources with Census
data.
• opportunity to work with users to understand emerging needs.
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UK Outputs
• The need for information about UK outputs is understood and something we still aim to provide.
• The decision to move the Scotland Census to March 2022 does create some challenges:
• Minor impacts on England and Wales Outputs (e.g. workplace populations in some areas).
• Higher level of impact on plans for UK Outputs:
• Timing and scope.
• Particular issues UK Origin-Destination outputs – meaning we need to think more creatively.
• A UK Data User Group is being set up to ensure user input will inform decision making
on UK Census Outputs.
• Given the role of census data in the wider Population Statistics system (e.g. Population Estimates)
the impacts ripple wider than Census, most likely around the timing and ‘neatness’ of changes at the
UK level.
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Key Dates
Date Activity
November/December 2020 Formal consultation on Census 2021 Output Geography
21 March 2021 Census day in England and Wales
Spring/Summer 2021 Formal consultation on Census 2021 outputs
Autumn/Winter 2021 Publication of Outputs Prospectus (incl. indicative release timetable)
March 2022* Census First Release
March 2022* to March 2023* Release window of main Census 2021 outputs (England & Wales)
March 2023* Completion of main Census 2021 outputs (England & Wales)
Late 2023/ early 2024 Release of UK Census outputs
* Target dates
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Useful links
• Census 2021 Outputs webpages
• Register for Census 2021 updates via GovDelivery
• Take part in Census 2021 outputs user research by emailing:
census.outputs@ons.gov.uk
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Summary
• Timely outputs in more flexible and accessible ways.
• Accompanying disclosure control changes.
• Outlined ONS Census Analysis plans.
• Potential for ‘rich content’ products.
• A reminder of the opportunity to respond to the Census Geography
consultation.
• Plans for a full consultation on Census Outputs in Spring/Summer 2021.
• We want to work collaboratively with users throughout to ensure our Census
2021 products and the ways users access them meet needs.
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Census 2021 Outputs
Any questions?
Visit www.sli.do and enter code 78579
Please complete our evaluation survey (we will email you a link) and let us know how we did.
If you have any questions email us on SDR.stakeholder.engagement@ons.gov.uk.
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