Is America becoming more urban? What portion of the population is now living in an urban (vs. rural) setting? With all the debates and discussions related to urban sprawl, do we have a way of defining and measuring where and to what extent that phenonmenon is taking place? The answers to all of these questions require that we have an agreed upon definition of what it means to be "urban" (or rural, since we presume the two categories to be mutually exclusive and exhaustive, i.e. that every person and piece of land in the nation can be assigned to exactly one category or the other.)
This web page will look at the latest official Census Bureau definitions of urban and rural and will identify resources for determining to what degree various geographic areas are classified as being one or the other. We shall also look at how and where to get census and other data that can help us see what differences there may be between the two area types (in terms of how many people, age distributions, income and poverty levels, etc.), and perhaps more importantly, what trends do we see related to them.
It may seem obvious in many cases: central cities are clearly urban, while most farms -- real ones, at least -- are clearly rural. But there is more and more development in places sometimes referred to as "exurbia", and in fringe areas located within or adjacent to smaller cities, where the urban/rural classification is much less obvious. Because the definition of this concept is so important, we as a nation feel obligated to keep trying to improve it. This is no doubt a good thing for the sake of having a better measure of what is going on just recently, but it creates problems trying to analyze trends when the definition changes over time. The current definition of Urban (which is also the definition of rural, since the two are complimentary) went into effect with the 2000 decennial census, and is based upon population density data collected in that census. Unless otherwise noted, all references to urban vs. rural in this document will be using this definition.
The Census Bureau's classification of "rural" consists of all territory, population, and housing units located outside of UAs and UCs. The rural component contains both place and nonplace territory. Geographic entities, such as census tracts, counties, metropolitan areas, and the territory outside metropolitan areas, often are "split" between urban and rural territory, and the population and housing units they contain often are partly classified as urban and partly classified as rural.
We have seen web sites (http://www.nhtsa.dot.gov/people/injury/ems/emstraumasystem03/glossary.htm, just to cite an example), where the defintion of Rural is presented as outside of an MSA (Metropolitan Statistical Area. While agencies may find it convenient to use such definitions and while there may be some merit and logic associated with these alternate definitions, it is important to keep in mind that these are not the official definitions and their widespread use just contributes to the confusion. It does seem easier and a bit less geeky just to say "rural" instead of "Non-metro". It may be okay until somebody wants to know how many people live in those "rural" areas.
You can also access summaries for such geographic components through American FactFinder. For example, if you choose the AFF "Data Sets" option and then choose the 2000 Decennial Census and Summary File 3 and Detailed Tables with a geographic summary level of state or above, then after your output is displayed (I know, not too cool) they provide a little menu bar that lets you "change your results". If you click on the "Options" pull-down you are presented with a "Geographic Components" choice. Follow the menus and make your choices. It's really pretty easy to generate tables for urban and rural portions of states and the nation. Understand, that what this means is that you can get all the other detailed tables, things such as income measures, poverty level tables, housing value mediams and distributions, propensity to live in mobile homes, etc. -- all this broken down not just by urban and rural but also by various subcategories of urban and rural, such as "Urban - in urbanized area - not in a central place" (which is what you might think of as "suburban").
Of course, if all you are interested in is how many persons and/or households within an area are classified as being urban and rural, that can be readily accessed from tables on files such as SF3. In our standard extracts based on Summary File 3 data (filetype sf32000x) we include the variables urban, rural, InUAs (living in Urbanized Areas), InUCs (living in Urban Clusters), OnFarms (persons living on farms), UrbanHUs (urban housing units) and RuralHUs. There are corresponding Pct variables for each of these items; e.g. PctUrban has the value of Urban as a percentage of the total population. All of these items, are derived from tables on Summary File 3. The definitions can be viewed in the online metadata . The data can be viewed within our standard sf3-based demographic profiles. We did not include any urban/rural data on our standard extracts based on Summary File 1 in the 2000 census because, although the tech documentation told us the data would be avaiable in Tables P2 and H2, the reality was that when those files were released those tables were not ready yet because it took so long for the Bureau to do the GIS-based processing that would permit assigning values to those tables. You can access those tables via American FactFinder, however.
Geographic Component summaries on census summary files is not new. Such summaries have always been published by the Bureau, although the number of categories has increased. Urban and Rural have always been the most important and widely accessed catgegories. Keep in mind, however, that the definitions have changed over time so the data are not entirely comparable.
The answer is that they geocode the address of the survey respondent, attaching (among other things) the 2000 census block. Then they assign the urban/rural code to the household/person based upon the code assigned to that census block as of 2000. Why not use the urban/rural code assigned to that block based on 2005 data?
Because that data does not exist. See item 4 in our Ten Things to Know about the American Community Survey - 2005 Edition document. The ACS is not about head counts, it is about characteristics of persons and households. In order to define a census block as being urban or rural would require having a complete set of current block population counts which would then have to be used as input to the Bureau's very sophisticated GIS-based program that examines complex density patterns in order to make the category assignments. So, how am I to interpret the 1,803,146 persons in "rural areas"? If this number is higher than the comparable figure from the 2000 Census, does it mean that people are moving from urban to rural areas? If by "rural area" you mean an area that was classified as rural in 2000, based on 2000 data patterns, then the answer is probably yes. But this does not (necessarily, or even probably) mean that we are abandoning urban settings to live in more rustic ones. That may be what we wanted to do, but what happens when people from urban areas move to areas that used to be rural but that are adjacent to urban areas, those areas are converted from rural to urban. It is just that we do not measure and recognize this conversion until after the next decennial census. Of course, it is always possible that in some areas it may have gone the other way, that some blocks formerly classified as urban have now become rural. But anyone who follows development patterns in the U.S. knows that this sort of change is almost unheard of, barring a natural or man-made disaster.
Bottom line on this point is that the figures for the rural portions of states and the nation that come from the ACS are probably counting too many people as being rural, with the correesponding under-counting of the urban portions. If you are studying urban sprawl and you want to use ACS data to look at how much land area has been converted from rural to urban as the result of sprawl, you should NOT be looking at the ACS geocomp summaries for Urban vs. Rural.
This map shows you what we were talking about in Item 6, above. Most of the rural population of Missouri (which is not at all an unusual state in terms of such things) lives in metropolitan or micropolitan areas. The figure we cited above that less than 3% of the land area of Missouri was classified as urban can be seen in this map. Although it does not display urban population explicitly, we know that it can only exist in an Urbanized Area or Urban Cluster. Urbanized Areas/Urban Clusters and Metropolitan/Micropolitan areas are very closely linked, with the UA/UC just being the densely settled core area of the metro/micro area. Urban territories on this map are green areas with no black dots. The St. Louis and Kansas City core areas are by far the largest such areas in Missouri. Most of the really dense clusters of black dots (rural population) are within the green areas, especially the dark green (Jefferson and Franklin counties just south and southwest of St. Louis, for example). The biggest cluster of dots in a non-metro-micro (white on the map) area is in the Lake of the Ozarks region, an area inhabited by early retirees and others seeking to get away from the big city. This area is only marginally classified as rural; with growth in the Osage Beach/Lake Ozark area this decade it is very likely that after the 2010 census we'll have a Lake of the Ozarks micropolitan area and Urban Cluster, which will result in a large portion of the area's population being reclassified as urban.
What many people think of when they think of a rural lifestyle is one where going "into town" involves a significant journey that may only happen maybe once a week or less. But that is really not the case with a great majority of the rural population now (if you are looking for that group, the better category would be persons living in the white areas of the map -- i.e., outside any Metro or Micropolitan area). The majority of the rural population today (in Missouri, at least) may have septic tanks and may not have access to city utilities and otehr services, but they do live within an easy drive of some population center, and the large majority, we suspect, have easy access to a Super WalMart. Most do not live on farms (only about 2.5% of Missouri's population lived on farms in 2000; that comes to about 1 of every 12 rural residents). Most live in areas that look very much like suburbs or in small towns like Hermann or Osage Beach. (The latter small-town residents were actually classifed as urban under the prior definition.)
The author acknowledges the valuable contribution of Lance Huntley, OSEDA, who produced the map in item 10.