Self Defined Ethnicity

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

Asian or Asian British

Black or Black British


  • M1 – White and Black Caribbean
  • M2 – White and Black African
  • M3 – White and Asian
  • M9 – Any other Mixed background

Chinese or other ethnic group

  • O1Chinese
  • O9 – Any other ethnic group


  • W1British
  • W2Irish
  • W9 – Any other White background

Not Stated

  • NS – Not Stated

See also


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