Capture and Coding

Overview

The completion of the 2022 census will be possible via an online questionnaire or by filling in a paper questionnaire. Providing the two options will maximise response for all groups of the population. Although the information will be collected from two different capture channels, responses will be given codes from consistent, recognised classifications.

Data Capture

The 2022 census will be the first one conducted primarily online. A key benefit of an online platform is that by improving the user experience, and maximising efficiencies in collection and processing of information, data quality will be maximised. Those who wish to complete a paper questionnaire will still be able to do so as it is important to achieve high response rates for all groups of the population.  Regardless of the method of completion, respondents will answer the same questions.

Coding

Responses from census questions are given numeric codes in order to produce outputs. NRS have created a coding specification that details how to code questionnaire responses in a format suitable for analysing. It contains publication classifications as well as logic for the IT systems known as “business rules” and “coding indexes”. Much effort was invested in creating the coding indexes as these provide valid codes for common misspellings or non-standard answers provided by respondents. To improve on data quality, the coding specification was also updated following lessons learnt from the October 2019 rehearsal evaluation.

Online data coding

For responses collected online accuracy of data capture is higher as the coding happens as the user completes the questionnaire. The online system has in-built features to increase the quality of the coding.  For example, "routing" bypasses certain questions if they are not relevant to an individual and "user-optimised indexes" provide a lists of suggested options to select an answer from.

Paper capture and coding

Coding accuracy is lower for paper questionnaires because there are limits to interpreting handwriting and respondents may not follow the guidance. Paper questionnaires are scanned and the responses coded using character recognition software. Extra techniques to correct for spelling mistakes and word ordering are applied to code text based questions.

Manual coding

Although time has been invested to maximise accurate coding at source there will be a proportion of responses that are not successfully matched to the coding indexes. These will need manual intervention with a person making a decision on the code given. 

Statistical Quality Assurance

NRS has published a Statistical Quality Assurance Strategy which provides more information on how coding processes will be quality assured in Census 2022.

UK Harmonisation

NRS also worked with the ONS to harmonise coding indexes where possible. This wasn’t always feasible as some question wording and categories differ between the census questionnaires designed by the ONS and NRS. Information on harmonisation on the questions is available on other pages of our website.

For more information on how National Records of Scotland work with the other UK censuses to harmonise our statistical methodology for UK Data Users, as well as share best practice and lessons learned, please see the UK Census Data tab of this website.

Stakeholder events

In February 2020, NRS ran Statistical Methodology Stakeholder events aimed at the general public and data users. These events gave attendees a high level overview of what happens to census data from when NRS receives census responses through to producing the Census 2022 outputs.

During these events, we sought feedback to help to further develop our plans to ensure the highest quality of outputs for our users. Slides from the event are published on the event page of the Scotland’s Census 2022 website.

Get Involved

NRS are seeking feedback on the content provided on these pages to help us provide the information most relevant to you. We will be developing more content on capture and coding processes in the near future so please visit this page again.

To share your views and information needs, please contact scotlandscensus@nrscotland.gov.uk.