RxA Cure for the Common Codes
2009 Version

Usage Notes   |   Related Sites

  • Alabama
  • Alaska
  • Arizona
  • Arkansas
  • California
  • Colorado
  • Connecticut
  • Delaware
  • District of Columbia
  • Florida
    • United States



    Usage Notes

    What and Why

    A Cure for the Common Codes is a collection of web pages - one page for each state in the U.S. and the District of Columbia - that display common geographic codes pertaining to the state. While all of these codes are somewhat readily available at various locations on the web, we think it will be very convenient to have a 1-stop site where they are all collected in one place and in a consistent, compact format. Codes included in the initial release are:
    • counties,
    • places (cities),
    • county subdivisions,
    • various kinds of metropolitan/micropolitan areas,
    • urban clusters and urbanized areas
    • school districts.
    It is intended to serve as a kind of geographic codebook showing the standard codes and the names associated with them. The codes are almost always ansi (American Natioanl Standards Institute). The only exception will be in cases, such as with School Districts, where there are no ansi codes. (The old FIPS codes are now called ANSI codes; they have not changed their values, just their name. See the     ANSI page at Census geography site.)

    In addition to displaying the codes the pages provide links in most cases to web sites where demographic profiles of the areas can be accessed. There are also access to the files within the Missouri Census Data Center's data archive which were used to generate each of the code tables. These links take you directly to the Dexter data extraction web utility which can be used to access the datasets. This page contains links (at the top) to detailed metadata describing the dataset and (at the bottom) to online power-point tutorials describing how the uexplore/dexter extraction software works.

    Finally, links are provided to closely related web pages where the user can find more detailed information regarding the codes. For example, in the Metropolitan / Micropolitan Statistical Area section we provide a link to a web site at the Census Bureau where you can find not only these same names and codes, but also see the counties that comprise each of the areas.

    Footnotes at the bottom of each table indicate the vintage of each set of codes. This can be a critical detail since many of these codes are volatile. Even county codes have had just a small number (2) of changes (in Colorado and Virginia) since the 2000 census. We will make every effort to update the application periodically so that we are always displaying the most current codes. We have, for example, gone back to the Bureau to get the most recent (as of December, 2003) definitions of ("core-based") Metropolitan and Micropolitan areas.

    Metropolitan Statistical Areas

    A special note is in order regarding this term. OMB (the U.S. Office of Management and Budget) is responsible for establishing the standard definitions of metropolitan areas for the purposes of collecting and publishing federal statistics. The standards used to define these entities have varied over the years. In 1980, for example, all we had were the Standard Metropolitan Statistical Areas (SMSA's). Each SMSA was assigned a 4-digit ansi code, unique within the country. In the early 1980's there were new standards adopted that resulted in a new collection of metro area definitions: the word "Standard" was dropped and we now had entities which were called simply "Metropolitan Statistical Areas" (MSA's). But we also got two new kinds of entities called Consolidated and Primary MSA's (aka CMSA's and PMSA's). When a large metropolitan area had more than one major city, each city and its surrounding counties became a PMSA, and the group of contiguous PMSA's formed a CMSA. For example, we had the Dallas and Fort Worth, Texas PMSA's, which together formed the Dallas-Fort Worth CMSA. Each MSA, PMSA and CMSA was assigned a unique 4-digit ansi code, most of which were inherited from the SMSA of the same or similar name. So, for example, 3760 became the code for the new Kansas City MSA, the same as the code already in use for the Kansas City SMSA. This scheme and the corresponding 4-digit ansi codes were in effect for about 20 years, and were used for tabulating the results of both the 1990 and the 2000 decennial censuses. These areas are displayed on these web pages in the table titled Metro Areas (MSA's, CMSA's and PMSA's as of 1-1-2000). Note that you do not have to worry about these codes ever changing since they are no longer the "current" codes.

    Then we have the other ("core-based") Metropolitan Statistical Areas, which were first defined in 2002. They were part of a new scheme that reflected our improved ability to define the metropolitan concept of a central densely populated area (the "central city") and the areas surrounding it. In the old scheme you had to start with an incorporated place of at least 50,000 population, but in the new scheme you just needed a central population core that was independent of any incorporated boundaries. As part of the new scheme we also got Micropolitan Statistical Areas for the first time; these are the same concept as MSA's, but with just a smaller core area requirement. The generic term used for the new metro/micro scheme was Core based statistical areas. But the Census Bureau has since decided that this term is somehow not useful and they have stopped using it. (There was no public discussion of this nor has it ever been announced. There was an internal memo and web pages were changed to reflect the decision. But if you look carefully, you can still see the term used in some of the footnotes and reference pages.) A major point to notice about these new areas is that they were all assigned brand new 5-digit ansi codes, reflecting the fact that these are brand new entities. Converting to the core-based areas is a much more significant break than what occurred when we went from SMSA's to MSA's in the early 80's.

    The concept of major subdivisions of very large metro areas in the new core-based scheme is implemented with the new Metropolitan Division entity. These are not shown on the state level pages in this application, but we do show all of them on the United States page. Similarly, we show there the new Combined Statistical Area codes and names only on the United States page. These would appear to be CMSA equivalents but it turns out they are not. Most CMSA's under the old scheme just became MSA's under the new scheme with metropolitan divisions.

    Table-related Hyperlinks

    Most of the tables on these pages have one or more hyperlinks following them, which are intended to help the user find more information about the entities in the table. Common links will take the user to a menu page from which they can access demographic profile reports based on the 2000 census. Another common link is to the Data Source for the table. The tables are generated using data tables stored within the MCDC's public data archive. We provide a web utility application called Dexter that allows users to access and extract data from these datasets. These hyperlinks to the Data Source will usually invoke the Dexter utility with the source data set specified. This will be of no interest to most users, but can be quite useful for those users who want to access the codes and names along with perhaps related data in various machine-readable formats.

    Some tables have See also hyperlinks after them. These will take you to other closely related web sites. In many cases it will take you to original source site, often at the Census Bureau. A good example is the See also link following the CBSA table for state pages, which takes you to the "metrodef.html" page at the Bureau where you can get the latest and most definitive information regarding these entities. On the comparable table on the United States page, the See also link takes you to a report generated by the Missouri Census Data Center that shows all the metro or micropolitan areas (we split them into two tables on the United States page) that shows what counties comprise the areas and what their total populations were from the 2k census along with the most recent estimates.

    State and County Codes

    The state ansi code is displayed as the first detail line of the state-level reports, along with the standard 2-character state postal abbreviation. The state ansi code is also repeated as the first 2 digits of several other codes on the page, such as the county code. (A semantics-based argument could be made that says the ansi county code for Autauga, Alabama is 001 rather than 01001. But, as a practical matter, most of the time when you want to provide a code for this county you will be required to provide the full 5 digits. So we give you more, rather than less.)

    Credits

    The application was developed by John Blodgett of OSEDA, under a contract with the Missouri Census Data Center (MCDC).    Nandini Basu of OSEDA did most of the programming to generate the code pages using the resources of the MCDC's data archive.


    Related Sites

    Questions and comments can be addressed to John Blodgett.

    URL: http://mcdc2.missouri.edu/webrepts/commoncodes/index.html