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 "18 + 1" codes, as there are 18 of them, plus one code (NS) for "not stated".[1] In addition to the previously used 16+1 codes, they contain the categories W3 and O2, while A4 is now replacing O1 (Chinese).[2]

The code system originated in the United Kingdom Census 2001 based on Recommendation 61 of the Stephen Lawrence Inquiry Report (SLIR).[2][3]

British police forces are required to use the SDE 18+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.

List of SDE codesEdit

Mixed or Multiple ethnic groups
  • M1 – White and Black Caribbean
  • M2 – White and Black African
  • M3 – White and Asian
  • M9 – Any other Mixed or Multiple background
Asian or Asian British
Black, Black British, Caribbean or African
  • B1Caribbean
  • B2African
  • B9 – Any other Black, Black British or Caribbean background
Other ethnic groups
  • O2Arab
  • O9 – Any other ethnic group
Not stated
  • NS – Not Stated.

See alsoEdit


  1. ^ "Criminal Justice System Exchange Data Standards Catalogue, Version 6" (PDF). GOV.UK. HM Government. Retrieved 16 July 2021.
  2. ^ a b The code systems used within the Metropolitan Police Service (MPS) to formally record ethnicity. 2 March 2007.
  3. ^ The Stephen Lawrence Inquiry. February 1999.