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‘Now you don’t see it, now you do’ – the dangers of hidden data

Blog posted by: Simon Rice, Group Manager for Technology, November 13, 2015 by 

spyman-redactionDetails of 2,000+ residents published online, a £70,000 penalty and an “extremely sorry” local council. That was the result of Islington Council being a little more transparent than it had intended, providing a freedom of information requestor with spreadsheets they didn’t realise included sensitive personal data.

It was, unfortunately, not an isolated incident. Whether it’s a response under the Freedom of Information Act or a reply to a subject access request, there are many different ways to inadvertently include personal data.

That’s prompted the guidance we’ve recently published: How to disclose information safely – removing personal data from information requests and datasets.

It gives practical advice on what to look out for when providing information in different formats. So take a look below at our ‘now you don’t see it, now you do’ examples of ways you could be getting it wrong, and then read the guidance to make sure you get it right.

Hidden columns

With spreadsheets, personal information can be hidden in plain sight. A hidden column is easily revealed, providing more information that you had intended. Check for hidden content, or use simple text formats like CSV files.

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