Ethnic migration

• Categorical variables

• 9 origins (O) and destinations (D)
• 16 age groups (A)
• 2 sexes (S)
• 4 ethnic groups (E)

• 1991-2007 National Health Service (NHS) register*

• OD, OAS and DAS tables each year

• 1991 and 2001 censuses

• ODAS and ODSE