What were the main changes in the way data was collected in the 2001 Census?

A key change concerned the rules that defined "where" people should actually be enumerated in the census. Previous censuses attempted to record people where they were on census night. For many people this differed from their normal place of residence. Thus while the 1991 Census required such people also be entered on forms at their normal address, the requirement for inclusion on two separate census forms was subject to confusion and resulting omission. This was greatly simplified in 2001, with information collected on individuals based solely on their home address (their normal residence).

A second major change was that for the first time, completed census forms were posted back in prepaid forms by the public, rather than being collected by enumerators.