Census 2021 and data protection

Today is Census day in the England and Wales1. Happening every ten years, the census provides a snapshot of households across the country to help shape funding decisions and plan for future needs (schools/public services etc).

As a data scientist and data ethicist, I am always urging individuals to be cautious with their personal data and when they give it up. As a recent example, at our first COVID-19 vaccination we were handed a questionnaire requesting a lot of personally identifiable information and medical history – these sheets were poorly photocopied and had no detail on why this information was being requested, who was requesting this information or how it was going to be used. Was it the NHS, the manufacturer of the vaccine, the logistics company managing the distribution, the religious leaders of the church hall where the vaccination was taking place, or even a relation of one of the volunteers who needed the data for a school project? As you would expect we refused to fill in these forms.

The census is different. While I have had some in depth conversations with many people about the likelihood of data misuse and the difficulty in ensuring that any data warehouse is fully secure, the people I know who work at the Office for National Statistics are doing an essential job and it’s important that we give them the information that they need.

The survey has evolved since it was first introduced in 1801 as little more than a headcount, with typical British style passive aggressive subversion leading to change, with the best example of this being the protest against the religion questions as the UK becomes increasingly more secular. As such, in 2001 the fourth highest religion in the UK was Jedi. Similarly, questions on relationships and gender have evolved to encompass modern thinking rather than binary options in previous years. Understanding changes in these aspects of the population are really important to ensure that services and support are targeted correctly, and I’d urge anyone who is comfortable answering these options parts to do so. There are several quick examples on how this data is used on the census website, and if you are unsure of the benefits then I’d encourage you to have a look. These are pretty high level but you can see some of the published statistics for 2011 on the ONS publications page. From the results and the high level stories, hopefully you can see how important this information is to shape our society.

But should we be giving up this information? Well, since it’s a legal requirement then yes :D. Although even if it was not, I would strongly urge everyone to do so as long as the safety and security conditions of personal data are met.

From a security point of view, there is a lot of pressure on the ONS to ensure that the results are both confidential and secure. They go far beyond the level required and expected by businesses in this regard, and this is protected by four separate legislations (GDPR, Data Protection Act 2018, Census Act 1920, Statistics and Registration Service Act 2007). Encryption of online forms is at the same level as online banking, with further measures to ensure security and privacy assessed and tested. Reports for this are released to the public and the ones for the 2011 census are available on the ONS website, with the impact assessment for the 2021 census also available. Census records are also sealed for 100 years to protect the privacy of the people involved2. Without visiting the facilities and seeing the security for myself3, I am as satisfied as I can be that they are doing everything they can to ensure privacy and security of data.

Despite the help of one of my cats trying to fill in some of the questions on my behalf with her morning dance on the keyboard :), I have submitted the answers for my household and look forward to seeing the summary statistics and the differences from 2011 when the initial results are released in about 6 months.

  1. Different agencies run the census for Northern Ireland and Scotland.
  2. Although maybe as life expectancy increases this should be revisited!
  3. Which is never going to happen 😀

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Dr Janet is a Molecular Biochemistry graduate from Oxford University with a doctorate in Computational Neuroscience from Sussex. I’m currently studying for a third degree in Mathematics with Open University. During the day, and sometimes out of hours, I work as a Chief Science Officer. You can read all about that on my LinkedIn page.