For most of the larger cities, census figures are further classified by sections within the city on the basis of certain population and economic characteristics. These sections are called census tracts. Business population figures may be available from numerous sources. The Yellow Pages of the telephone directory and the city directory are local sources that are immediately available. Chambers of commerce, trade associations, and government agencies can often be helpful.
Many trade associations report the results of research on consumer expenditures.
Planning commission offices, 2. Employment offices, 3. Research done by newspapers, 4. Building permits, especially in newly developed areas, and 5. Mortgage and loan companies.