Domicile code

Notes: Since September 2008, domicile code has been automatically populated from the NHI at the time the cancer event is created. As such, the caveats around the domicile code in the NHI should also be considered here. For instance, it should be noted that before the NHI moved to its new platform in 2012, the address fields in the NHI were free-text with little validation. This meant there could be considerable variability in accuracy, which, in turn, meant addresses could not always be successfully geocoded to a domicile code, or could result in rural addresses being assigned to an urban domicile code where there was insufficient data to generate the correct code. This is because the automated geocoding software relies on generating a post code in order to determine where in a related table it should look to find the code. However, a number of validation checks were included when the NHI moved to its new platform and the quality of address information should improve markedly. The domicile code is taken from either the 1991, 1996, 2001, 2006, or 2013 census domicile codes depending on the year of diagnosis. If the year of diagnosis was between:

• up to 31 December 1997, the 1991 code is used
• 1 January 1998 – 31 December 2002, the 1996 code was used
• 1 January 2003 – 31 December 2007, the 2001 code was used
• 1 January 2008 – 30 June 2015, the 2006 code was used
• 1 July 2015 onwards, the 2013 code was used.

For retrospective cancer registrations (.e, late notifications) the domicile code was assigned from the appropriate census code table relating to the year of diagnosis. In such cases, the domicile code may not truly represent the domicile at the time of diagnosis, as the address at the time of diagnosis may not be reported.