There is a two-phase approach to processing and release of Census data. Easy-to-process topics, which comprise the majority of the Census topics, are included in the first release of the data. These include the critical counts for persons and dwellings for Collection Districts. The remaining topics, which require more complex processing, are included in the second release.
For a list of first release and second release variables, see the 2006 Census Release Strategy in the front of this dictionary.