= SOP Pseudonymised

Tags: [[SOP_Category]]

== Tools

- [[https://www.openpseudonymiser.org/|OpenPseudonymiser]]

== Sources

- [[https://ico.org.uk/media/1061/anonymisation-code.pdf|ICO Anonymisation Code of Practice]]
- [[http://webarchive.nationalarchives.gov.uk/20130502102046/http://www.connectingforhealth.nhs.uk/systemsandservices/pseudo/ref1term.pdf|Connectiong for Health Pseudonymisation Implementation Project]]

== General Principle

Individuals should not be identifiable or re-identifiable from the data that we publish, release to other organisations (including University of Leicester employees) or use internally unless absolutely necessary, for example to mail the individuals or search their medical records.

Therefore, we need to remove identifiable fields from data wherever possible.

== Identifiable Data

=== Names and addresses

Name and address fields should not be released unless required for the specific purpose of the data, such as mailing the participant.

=== Postcode

Post codes could possibly lead to re-identification depending on the number of households within the post code and the other fields released along with the post code.  According to the [[https://ico.org.uk/media/1061/anonymisation-code.pdf|ICO Anonymisation Code of Practice]] the number of households per post code are:

- Full postcode = approx 15 households (although some postcodes only relate to a single property)
- Postcode minus the last digit = approx 120/200 households
- Postal sector = 4 outbound digits + 1 inbound gives approx 2,600 households
- Postal district = 4 outbound digits approx 8,600 households

Therefore, a postcode should be truncated to increase its anonymity.

==== Alternatives to Postcodes

If possible, an alternative to postocde should be used.  These include:

- Townsend deprivation Index
- LSOA - Lower Layer Super Output Area

For both see [[Townsend Deprivation Index]]

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