The stability of ethnic identity in England and Wales 2001–2011

The instability of ethnicity measured in the national census is found to have doubled from the period 1991-2001 to the period 2001-2011, using the Longitudinal Study that links a sample of individuals' census records across time. From internal evidence and comparison with results from the Census Quality Survey and the Labour Force Survey, estimates are made of instability due to changing question wording, imputation of missing answers, proxy reporting, recording errors and changes in the allocation of write-in answers. Of the remaining instability, durable changes of ethnicity by individuals are thought to be considerably less common than changes due to a person's sense of identity not closely fitting the categories offered in the census question. The instability creates a net change in size of some ethnic groups that is usually small compared with the change in population between censuses from births, deaths and migration. Consequences for analysis of census aggregate and microdata are explored.