Page:Geographic Areas Reference Manual (GARM).pdf/179

 Many States in the southern and western parts of the United States had few or no subcounty governmental units that could serve as an adequate geographic framework for census purposes. The MCDs in those States frequently proved difficult to enumerate because their boundaries and names were not well known locally or were subject to frequent change. Also, these MCDs presented problems in the data tabulations because they often divided incorporated places into many component parts. This cluttered the census tables with superfluous lines of data, many with very small populations that were not meaningful to data users or that yielded statistically unreliable data from the questions asked of only a sample of households. In addition, most data users found these MCDs unsatisfactory for purposes of statistical analysis because of frequent name changes and boundary shifts that resulted in a lack of geographic comparability. These changes made it difficult—or impossible—to use these MCDs as a stable spatial unit for historical comparisons.

In order to provide a more useful set of geographic entities for data tabulation and analysis, the Census Bureau worked with State and local officials to establish a statistically equivalent subcounty unit that it called the census county division (CCD). The State of Washington was the first to implement CCDs and did so in time for the 1950 census publications. During the 1950s and 1960s, State officials and the Census Bureau replaced MCDs with CCDs in 19 more States. A twenty-first State, North Dakota, adopted CCDs for the 1970 census; shortly thereafter, it opted to return to MCDs—a decision based on the financial advantages of having MCDs that qualified for Federal Revenue Sharing funds rather than any disenchantment with the advantages of CCDs for statistical purposes. For the 1990 census, CCDs were established in the State of Nevada, making a current total of 21 States with CCDs. The adoption of CCDs has constituted a major change in the subcounty geography for a substantial part of the Nation. For detailed information on the origin and development of CCDs, the reader should consult Census County Divisions, Past and Future. Notes and References 8-8County Subdivisions