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Publication, Part of

Registered Blind and Partially Sighted People, England 2019-20

National statistics

National Statistics

Data Quality Statement


This data quality report aims to provide users with an evidence-based assessment of the quality of the 2019-20 statistical output from the SSDA902 return, reporting against the nine European Statistical System (ESS) quality dimensions.

SSDA902 data, collected in 2020 through the Short and Long Term (SALT) return, relates to the registers of blind and partially sighted people maintained by councils with social services responsibilities. It collects data on the numbers of people on each register at the end of the year and the number of new registrations during the last year. Data are also requested on the number of registered blind and partially sighted persons who have an additional disability.

This report provides information on the known data quality issues within the 2019-20 Registered Blind and Partially Sighted People report and accompanying data, in order to allow the reader and users of the data to understand any limitations of the data. This document should be used in conjunction with the publication’s data quality summary, report and associated data files

Further guidance and the tables for each collection are available


The degree to which a statistical product meets user needs in terms of content and coverage

Data for all people registered blind and partially sighted are collected from all 151 councils with social services responsibilities.

The data are used by central government to monitor the impact of social care policy and by local government to assess their performance in relation to their peers. This is also available for use by researchers looking at council performance, the RNIB to understand the population of people they intend to support, and by services users and the public to hold councils and government to account.

Accuracy and reliability

The proximity between an estimated value and the true value.

The accuracy of the data is the responsibility of the Local Authorities who submit the data to NHS Digital. The SSDA902 return is an aggregate collection and as NHS Digital does not have access to the individual records behind the aggregate counts, we are reliant on Local Authorities to assess their own data quality.

The submission and validation process for each collection is carried out as follows:

  1. The Local Authority collates the data for submission in the relevant collection form. This form includes inbuilt validations to allow councils to check their data for common issues prior to submission.
  2. Local Authority submits data by the mandated deadline
  3. All Local Authorities who met the deadline receive a data quality report covering critical validations and also providing some derived totals allowing councils to confirm their data is correct
  4. NHS Digital reviews the quality of all files submitted and may provide additional support to local authorities with significant data quality issues
  5. Local Authorities are able to resubmit data to amend any identified quality issues
  6. Final deadline for submission
  7. Following the final deadline NHS Digital will carry out analysis of the quality of final deadline. Although Local Authorities cannot resubmit data after this point, they may be contacted for additional clarification or context.

The validation checks carried out throughout this process include:

  • Checks for missing data items
  • Checks against the previous collection

The final validations consisted of looking at the responses to validation checks mentioned above to see if there are clear instances where data are implausible or Local Authorities have submitted data not in line with the guidance for the data collection and contacting the councils where necessary.

Common issues councils advised us of include: disability data not being routinely recorded, difficulties accessing data on clients aged under 18 and deceased clients not being removed from the register.

People that have a Certificate of Vision Impairment from an ophthalmologist choose whether or not to be included in their Local Authority’s register of blind or partially sighted people; registration is not automatic. This means that not everybody that has been certified as having vision impairment is recorded on a Local Authority register. For this reason, the data in this publication cannot be considered as definitive numbers of blind and partially sighted people.

The statistics relating to blind people who have an additional disability may understate the true numbers. This is partly because there is no advantage to a blind person in being registered as having additional disabilities.

Where there was information on additional disabilities for people having multiple disabilities including deaf or hard of hearing, Local Authorities were advised to count this under the category of deaf or hard of hearing. This could lead to a bias towards deaf or hard of hearing disabilities.

Missing Local Authorities

All 151 Local Authorities submitted the SSDA902 return. A number reported difficulties in completing the additional disabilities section of the data return.

Full details of completeness are available in the Data Quality summary.

All 151 local authorities submitted a data return. In previous years there were 152 local authorities. However, on the 1st April 2019 Bournemouth and Poole merged to form the new Bournemouth, Christchurch and Poole (BCP) local authority. The inclusion of Christchurch has also reduced the size of the Dorset local authority.

Therefore, care should be taken when making comparisons over time for Dorset due to such changes; when considering any changes at local authority level in this publication, these have been done on a like for like basis, excluding these two authorities.

Timeliness and punctuality

Timeliness refers to the time gap between publication and the reference period.

Punctuality refers to the gap between planned and actual publication dates.

The data relate to the period ending 31 March 2020 and therefore the lag from the end of the financial year is around eleven months. Due to extra pressures faced by local authorities due to the Covid pandemic, deadlines were extended to allow more time to submit Adult Social Care statutory returns; this meant the original deadline of 8th July was extended to 10th August, and the publication schedule had to be revisited and prioritised accordingly.

This publication has been released in line with the pre-announced publication date and is therefore deemed to be punctual.

Accessibility and clarity

Accessibility is the ease with which users are able to access the data, also reflecting the format in which the data are available and the availability of supporting information. Clarity refers to the quality and sufficiency of the metadata, illustrations and accompanying advice

This publication is now available in HTML, in order to meet the Government Accessibility Standard. Reference data tables are available to download from the NHS Digital website in Excel (.xlsx) and comma-separated values (.csv) format to allow the user access to the underlying data.

Data in the commentaries and tables of this report have been rounded to the nearest five. Values of 0,1,2,3 and 4 have been suppressed.

Coherence and comparability

Coherence is the degree to which data derived from different sources or methods, but that refers to the same topic, is similar

Although not directly comparable, the Public Health Outcomes Framework (PHOF) includes an indicator for preventable sight loss which draws on data from Certification of Vision Impairment (CVIs); 4.12iv - Preventable sight loss - sight loss certifications. CVI figures map well to registration figures – in 2016-17, the latest data point where both certification and registration data are available, there is a high level of concordance (20,605 registrations in 2016-17 compared with 23,453 certifications; 87.9%).

Comparability is the degree to which data can be compared over time and domain, for example, geographic level

For changes over time, see previous publications available

As part of the data validation process, councils provide feedback on data quality, available in the Data Quality summary.

Trade-offs between output quality components

Trade-offs are the extent to which different aspects of quality are balanced against each other.

For the 2019-20 reporting period, two submission periods were made available for councils. This was consistent with last year’s return. Data Quality reports and support were made available to those councils who submitted by the first deadline. Local Authorities were able to make updates to their first cut of data during the validation period.

Assessment of user needs and perceptions

The processes for finding out about users and uses, and their views on the statistical products

User feedback on the format and content of the 2019-20 Registered Blind and Partially Sighted People report is invited; please send any comments to [email protected]

Information about the 2019-20 Social Care collection materials is available. 

Performance, cost and respondent burden

The SSDA902 data were collected as part of the SALT return data, and the data collection process used in this publication is subject to assurance by the Data Standards Assurance Service (DSAS) (previously known as the Challenging Burden Service (CBS)). This is to ensure that data collections do not duplicate other collections, minimise the burden to all parties and have a specific use for the data collected. Learn more about DSAS.  

The burden of this collection has been assessed and approved, the burden of any changes to the collection are similarly assessed, to ensure that they do not create undue burden for local authorities.

Confidentiality, transparency and security

The procedures and policy used to ensure sound confidentiality, security and transparent practices

National Statistics

National Statistics status means that official statistics meet the highest standards of trustworthiness, quality and public value.

All official statistics should comply with all aspects of the Code of Practice for Official Statistics. They are awarded National Statistics status following an assessment by the Authority’s regulatory arm. The Authority considers whether the statistics meet the highest standards of Code compliance, including the value they add to public decisions and debate.

It is NHS Digital’s responsibility to maintain compliance with the standards expected of National Statistics. If we become concerned about whether these statistics are still meeting the appropriate standards, we will discuss any concerns with the Authority promptly. National Statistics status can be removed at any point when the highest standards are not maintained, and reinstated when standards are restored.

All publications are subject to a standard disclosure risk assessment prior to issue, which is approved by the Head of Profession for Statistics. Disclosure rules are carried out in line with the NHS Anonymisation standard.

Statistical Governance Policy

Freedom of Information Process

Statement of Compliance with Pre-Release Order [Archive Content]

Small Numbers Procedure

Last edited: 24 February 2021 1:53 pm