users require a stable set of boundaries that permit historical comparisons; others require updated boundaries that delimit the changing situation. Such considerations underlie the choice and use of a geographic area for each and every data use.
Before undertaking a census or sample survey, the Census Bureau reviews the geographic areas it currently uses. This review may include an evaluation of the entities at each level in terms of established or prevailing statistical practices and needs. Although generally there will be no major changes to most types of geographic entities, the Census Bureau always seeks to find better and more efficient geographic solutions if they exist, to devise new geographic approaches if they can be justified and implemented, and to drop or modify old geographic concepts that no longer serve their original purpose or are no longer cost-effective.
The following factors influence the Census Bureau in selecting an appropriate geographic framework for each of its censuses and sample surveys:
- Legislation
- Federal agency needs
- Tribal, State, local, and other needs
- Census Bureau confidentiality
- Technical and budgetary considerations
- Need for a general consensus on geographic concepts by data users
The weight and importance of any given factor may vary according to the specific purpose at hand and the particular application.
