Self Defined Ethnicity (SDE) codes
are a set of codes used by the Home Office
in the United Kingdom
to classify an individual's ethnicity according to that person's self-definition.
The codes are also called "16 + 1" codes, as there are 16 of them, plus one code (NS) for "Not Stated".
The code system originated in the United Kingdom Census 2001.
British police forces are required to use the SDE 16+1 codes (as opposed to the commonly-used radio shorthand IC codes) when spoken contact has taken place and an individual has been given an opportunity to state their self-perceived ethnicity.
Self Defined Ethnicity (SDE) Codes – 16+1
- M1 – White and Black Caribbean
- M2 – White and Black African
- M3 – White and Asian
- M9 – Any other Mixed background
Chinese or other ethnic group
- O1 – Chinese
- O9 – Any other ethnic group