By , however, this was reversed: almost 60 percent lived in suburbs and only 40 percent in the central city Table In every census since , the suburban-area population has grown at a more rapid rate than the central-city population Heilbrun, However, the regional variations are substantial.
From to , the central-city population grew by only 3 percent in the East and the Midwest, but it increased by 17 percent in the South and 24 percent in the West.
Despite frequent references in the popular press to "back to the city" movements, the movement of people into the city from the suburbs in the mids continued to be overwhelmed by people moving from the city to the suburbs Kasarda et al. This is, of course, not inconsistent with the revival of specific selected neighborhoods in cities. Despite the slow growth or decline of many of the cities in the Northeast and the Midwest, central cities nationwide have retained their share of the U.
Cities accounted for Note: Metropolitan areas as defined at each census since Data for exclude Alaska and Hawaii. Suburbs of metropolitan areas, in contrast, increased their share from 15 to 31 to 46 percent over the same time periods, almost completely at the expense of nonmetropolitan areas see Table Metropolitan areas are characterized by substantial spatial clustering with respect to both race and income.
Minority populations are particularly concentrated in central cities. Although nationally only 25 percent of non-Hispanic whites lived in central cities in , 57 percent of all blacks and 52 percent of all Hispanics lived in these areas see Table As a consequence, central cities are disproportionately the home of minorities, and suburbs are disproportionately the home of whites.
In , 21 percent of central-city residents were black compared with 7 percent in the suburbs; 15 percent were Hispanics compared with 8 percent in the suburbs Frey, However, there were important variations among metropolitan areas. In the Detroit metropolitan area, for example, 66 percent of the central-city population was black compared with 4 percent in the suburbs; in Los Angeles-Long Beach, 14 percent of the city population was black compared with 9 percent in the suburbs.
Racial segregation is extraordinarily high in most U. The conventionally used measure of segregation is the dissimilarity index, which. The average black-white dissimilarity index for metropolitan areas in was 66 Jargowsky, Among the 15 most populous metropolitan areas, the dissimilarity index for ranged from a high of 87 in Detroit to a low of 56 in Seattle.
Since school attendance is largely based on residential patterns, school segregation is also quite high. In , 66 percent of all black students and 73 percent of all Hispanic students attended schools that were predominantly minority, and 34 percent of each group attended schools that were 90 to percent minority Orfield et al.
There is general agreement that segregation, as measured by the dissimilarity index, has been declining slightly over time. Examining the 30 metropolitan areas with the largest black populations, one study suggests that black-white segregation declined 8 percent, from an average of 81 in to 73 in Massey and Denton, Table 8.
Over the s, another study reports that the average dissimilarity index between blacks and non-Hispanic whites fell from 70 in to 66 in , and that of the metropolitan areas actually experienced decline in the index over the period Jargowsky, Farley and Frey report that the average index of dissimilarity for metropolitan areas with significant black populations declined from 69 to 65 over the same period.
Modest declines are reported since in the proportion of blacks and Hispanics attending predominantly minority schools, and massive drops are reported in the percentage of blacks attending schools that are 90 to percent minority from 64 percent in to 34 percent in ; however, the percentage of Hispanics attending such schools actually increased from 23 to 34 percent over the same period.
Virtually all of the improvement occurred in the early years of that period, and there have been slight increases in the segregation of schools since the late s Orfield et al. In , 60 percent of the population of metropolitan areas living in households below the poverty level lived in central cities, compared with 40 percent in suburbs.
Economic segregation also exists throughout the entire metropolitan area and, unlike racial segregation, is growing. Using a dissimilarity index as a means of measuring the economic segregation of the poor in metropolitan areas that is, the proportion of the poor who would have to move in order to achieve an even distribution of poor people by census tracts across the metropolitan area , one study found that the mean value for households with income below the poverty level in the largest metropolitan areas rose from 33 in to 36 in , an increase of 11 percent Abramson et al.
The residential racial segregation of blacks is not simply a by-product of economic segregation. As described by Massey and Denton , the average level of segregation for blacks, as measured by the dissimilarity index, in the 30 metropolitan areas with the largest black population varies hardly at all by black income. High-income blacks live in areas nearly as segregated as do low-income blacks. Massey and Denton note that this pattern contrasts sharply with that of both Hispanic and Asian segregation, which ''begins at a relatively modest level among the poor and falls steadily as income rises'' In addition, the level of income segregation is markedly lower than the racial segregation dissimilarity indices.
The average racial segregation dissimilarity index for the metropolitan areas examined by Cutler and Glaeser was 59 percent, and the average income segregation dissimilarity index measured by examining what percentage of the bottom quartile of the income distribution for all households would have to move in order for each census tract to have the same percentage of low-income people as the entire area was 22 percent.
Likewise, for the largest metropolitan areas, Abramson et al. The unequal distribution of poor people across metropolitan space tells only part of the story; equally important is the issue of concentrated poverty. As of , 5 percent of the total population of metropolitan areas lived in high-poverty areas, an increase from 3. However, 17 percent of metropolitan-area blacks and 11 percent of Hispanics lived in such areas Jargowsky, In , 18 percent of all poor people in metropolitan areas lived in high-poverty areas, but, for the black poor, the figure was 34 percent compared with 26 percent in and for Hispanics, 22 percent slightly down from 24 percent in Contrary to much of conventional popular wisdom, suburbanization trends are long-standing.
Suburbanization in the United States can be traced back to the s, with the major surge beginning in the s; the decades following World War II were not unusual in their suburbanization trends Fischel, this volume. This suggests that many of the factors cited as explanations for suburbanization, such as the federal mortgage insurance programs of the s, the interstate highway system of the s, and the racial tensions, fear of crime, and poor city schools of recent decades, can at best be only partial explanations.
As Mieszkowski and Mills observe, these "are all postwar phenomena, and are mostly provincial U. In reality, the trend toward suburbanization has been prewar as well as postwar, and has been international in scope. There are two different types of explanation for suburbanization Mieszkowski and Mills, The first relies on the standard location model of the urban economist and involves improvements in transportation infrastructure which reduce the costs of commuting , technological changes that allow employment decentralization, and long-term increases in household income that allow households to act on their preferences for greater space.
The second class of explanations stresses "push" factors related to the fiscal and social problems of cities, such as high taxes, inadequate public schools and other government services, racial tensions, crime, and poor city amenities Clearly the two types of explanation are not mutually exclusive.
Margo projected incomes onto household location patterns and estimated that 43 percent of suburbanization between and was due to rising income cited in Fischel, this volume. After considering other possible causes, Fischel concludes, "it seems reasonable to guess that perhaps a quarter of Americans' move beyond the limits of central cities may be accounted for by factors other than mostly benign 'natural' economic trends.
There is yet another explanation, unrelated to population out-migration, whether driven by pull or push factors. Danielson argues that "the political separation of city and suburbs is not the product of 'natural' forces which caused the city to cease to expand and independent suburban jurisdictions to grow up around the urban core.
Until the last part of the 19th century, out-migration simply resulted in expansion of the city boundaries and was not accompanied by creation of politically independent suburbs. After that time opposition to annexation increased on the part of middle-class neighborhoods at the city's edge, and state laws permitting easy incorporation and making annexation more difficult resulted in an end to city expansion.
This objective was rooted in class and ethnic conflict and the desire of middle-class areas for local control over their relatively homogeneous communities. There is ample evidence that the spatial distribution of the U.
Downs vigorously argues: "the disproportionate concentration of poor households within central cities arises from the fundamental institutional structure of U.
This structure may seem 'natural' or the result of 'free market forces,' but it is neither. In fact, other structures prevail in most of the world. Likewise, Fischel this volume states that where the poor live relative to the rich within metropolitan areas is an empirical question rather than an inevitable result. Similarly, Danielson argues that "public policies have played a central role in the development of a spatially differentiated metropolis in which blacks are separated from whites, the poor from the more affluent, the disadvantaged from economic and educational opportunity.
The distinctively American political institutions that give rise to spatial patterns of residential location are local control of land use decisions, state laws permitting easy incorporation of municipalities, and a fiscal system that requires municipal governments to finance most of their local services from their local tax base Danielson, The ease of municipal incorporation permits the creation of many local governments within metropolitan areas.
The motive for incorporation is to exercise land use controls at the local level in order to exert control over the local setting. As a consequence, Americans with sufficient resources are able to influence who their neighbors are by using land use controls to raise the price of housing beyond what lower-income households can afford.
In addition, the fiscal system facing local governments in the United States provides incentives to keep poor people out, since low-income households will consume more in public services than they will contribute in local taxes. As Downs describes the process :. In most U. These people want separate jurisdictions in part because they do not want certain externalities affecting them that are regulated by some broad government that reflects the interests of persons living throughout the metropolitan area.
Many suburban residents also want to live in neighborhoods occupied primarily by households with incomes equal to or higher than their own, similar cultural values and outlooks, and similar racial or ethnic backgrounds.
They also fear that the proximity of lower-income households will reduce the market values of their. And a large group of low-income households within their jurisdiction might cause their local governments to raise taxes to provide the services needed by such households. Local government action permits and facilitates this spatial segmentation, and local control of land use is the critical linchpin that encourages fragmentation and thus results in economic stratification Danielson, Although research is sparse, comparative social policy experts frequently observe that the degree of economic segregation in urban areas is much higher in the United States than in many other western nations in which land use controls are not exclusively local Berry, ; Sellars, Fischel this volume argues that, although income segregation by neighborhood is probably inevitable, it is greatly accentuated by modern zoning.
He observes:. Although I regard neighborhood income segregation as likely to occur under almost any mechanism that operates without a strong dose of coercion, it must be emphasized that income segregation is greatly accentuated by modern zoning. It is one thing to observe that the rich and poor live in different neighborhoods separated by a thoroughfare, a cemetery, or a railroad track.
It is something of a greater order of magnitude to observe that they live in entirely different municipalities separated by miles of low-density development or natural preserves. The latter separation surely discourages economic and social interactions that would otherwise be mutually beneficial and that are the cornerstone of a prosperous, democratic society.
But zoning also plays a role in contributing to allocative efficiency in metropolitan areas. Tiebout and others Ostrom et al. Each jurisdiction thus attracts a set of residents who have similar preferences for services. As Mills and Oates observe, however, "Once we recognize that the demand for public services is systematically related to income, we see that the Tiebout model implies powerful tendencies toward segregation by income level.
It does so by preventing lower-income residents from moving into higher-income areas with high tax bases, thus enjoying a level of services at a lower tax price than they could otherwise afford and achieving a fiscal subsidy from their wealthier neighbors Bradford and Oates, ; Hamilton, There is a variety of means by which local governments are able to use land use regulation to control access to their community and to exclude lower-income and, consequently, many minority households.
Exclusionary zoning techniques include requiring a minimum lot size or a minimum number of square feet for any home built on the lot, thus increasing the cost of new housing, and prohibiting. In addition, unreasonably high building code standards and strict subdivision requirements may also raise the cost of housing beyond the means of lower-income families. The recent explosion of residential community associations may also be serving exclusionary purposes.
Weiher contends that exclusionary techniques are one part of a two-part process that results in sorting by income and race. The other part involves the role of political boundaries in providing a proxy for a set of information about the jurisdiction that provides cues to persons making location decisions.
He argues that "political boundaries support the recruitment that is the complement to exclusion in urban sorting.
Specifically, there should be a higher degree of segregation by salient characteristics in the United States. No definitive work has been done on this subject, but there is anecdotal evidence to support this hypothesis. Berry comments on the relative lack of segregation by race and class in Britain and Western Europe. There is evidence that the ease of municipal incorporation promotes the creation of large numbers of local governments, a precondition for income stratification by jurisdiction Nelson, ; Burns, The existence of more local governments permits households to sort themselves out by income, and research has shown that the number of local governments is associated with more income stratification.
Studies by Hamilton et al. For a review of the empirical research on sorting, see Dowding et al. Burns contends that since the desire to segregate by race has been more important than the desire to segregate by income as a factor in explaining the creation of new municipal governments.
Employing multivariate analysis to explain variation in the incorporation of new municipalities in a sample of counties, she found that the number of nonwhite people in the county had a significant and more substantial impact on incorporation than did the number of poor people. Weiher makes a similar argument and found, using analysis of variance, that segregation by race, education, and income over the period came to be organized more by city than by neighborhoods within cities.
He argues that a series of policy changes, primarily through court rulings, have made segregation by race within jurisdictions subject to legal action, but has rendered segregation at jurisdictional boundaries legally secure. Central-city residence has adverse effects in many metropolitan areas in two obvious ways. First, fiscal disparities frequently impose higher tax burdens on residents and provide them with lower-quality services than would be the case if they lived in a suburb with the average area tax capacity.
The result is a reduction in the income and well-being of city residents, a penalty for city living. Second, the movement of jobs from the central city to the periphery and the reduction of low-skilled jobs in the city make it more difficult for city residents to gain access to jobs and lead to the problem of spatial mismatch.
A healthy central city affects the well-being of its residents. And, as discussed below, it also affects the well-being of suburban residents and the nation.
Central cities have provided the agglomeration economies that have powered metropolitan growth. They have also functioned as the port of entry, socialization, and assimilation for immigrants, providing them with low-cost housing and opportunities for economic advancement. Daniel i notes that, of the 8. Can central cities continue to perform these traditional functions? Is the central city still viable?
The traditional rationale for the economic contribution of cities is that agglomeration economies provide a competitive advantage for firms locating in cities; they are seen to be the driving force in the development of the metropolitan economy. Agglomeration economies are cost savings to firms that result from their locating in urban areas. Such economies are of two types. Localization economies are savings that result from a firm locating near other firms in the same or related industries.
Urbanization economies are economies that result when the production costs of a firm decline as the aggregate level of economic activity expands within the area. Mills and Lubuele cite Henderson's estimate that metropolitan-area output per unit of input increases 4 to 6 percent for each doubling of its population.
According to Ihlanfeldt , agglomeration economies have three causes: labor market economies, scale economies in the production of intermediate inputs, and communication economies. He observes that the last two of these clearly favor central cities. There is general agreement that agglomeration economies still exist and provide important advantages to metropolitan economies. But there is the question of whether they can now be achieved at lower densities in the suburbs.
Some researchers argue that suburbanization of office development and the growth of "edge cities" Garreau, provide the same opportunity for agglomeration economies that exists in central cities, and thus cities have lost their competitive advantage Hicks, ; Hartshorn and Muller, Others contend that telecommunications advances will soon make it possible to transact business without the need for face-to-face contact, again eroding the advantage of cities.
Danielson and Wolpert argue that a new metropolitan form is emerging in the suburbs that, by implication, reduces the significance of the central city:. This new metropolis is a new urban form, the latest stage in an evolving process. The vibrant world of the new metropolis encompasses corporate headquarters, new industries such as aerospace and electronics, research laboratories and health complexes, massive malls and lesser retail clusters, hotel and convention centers, arenas and stadiums, government offices and university campuses.
These developments produce a sprawling landscape of low-density settlement punctuated by nodes of intense activity usually located at major intersections of radial expressways. As the new metropolis evolves, the original central business district becomes one among many centers, with its own specialized activities and market niche.
Muller observes that "globalization forces intensify and accelerate the suburban transformation of the American city. A new urban future is being shaped as fully developed suburbs become the engine driving metropolitan and word city growth.
There are, however, counterarguments. First, as Clapp argues, even though telecommunication technology may permit interaction, people still may enjoy face-to-face interaction more and gain more from it. Indeed, Mills makes a distinction between ambiguous and unambiguous information, with the former inevitably requiring face-to-face exchange regardless of the state of telecommunications technology.
Ihlanfeldt has examined evidence on the extent to which central cities retain the advantages of an agglomeration economy, observing that empirical research on this question has been sparse. He nonetheless cites studies indicating that face-to-face contacts continue to be an important determinant of the location of office activity.
He also has reviewed evidence on the type of firms. If not, why would firms be willing to incur the otherwise high production costs associated with a central-city location?
Nevertheless, the growth of information-processing employment in the suburbs indicates that central cities may be losing their locational advantage over time" Indeed, a multivariate analysis of municipalities' share of employment growth for each decade from to in the New Jersey suburbs of New York City found that physical proximity to New York was of declining importance in determining employment share Danielson and Wolpert, They observed that the initial comparative advantage of the densely settled cities "based upon proximity to New York City, good commuter access, and existing agglomeration of population and employment offered less attraction to firms and residents with a clear preference for lower density sites and highway and road access.
A review of the literature by Mills and Lubuele states that "all recent studies conclude that inner cities [central cities] remain important and integral parts of their MSAs. Many suburban residents appear to believe that their suburbs are functionally independent of the central city and that central-city problems do not affect them at all. This view is shared by some knowledgeable researchers as well.
Hartshorn and Muller write: "With surprising speed in the '70s and '80s, suburbs have evolved from loosely-organized 'bedroom community' into a full-fledged 'outer city,' characterized by metropolitan-level employment and activity concentrations and functional shifts that amount to nothing less than the achievement of suburban economic, social, and geographic independence from the nearby central city that spawned these satellite settlements several decades ago.
Others go so far as to argue that it is the central city that is now dependent on the suburb Bingham and Kalich, Their evidence for this dependence is the need of the central city to supply qualified workers for its high-skilled jobs. Furthermore, at least in cities that have an income tax, the city is dependent on this suburban workforce for a substantial portion of its revenues. It can also be argued, however, that suburban residents are dependent on the city for their jobs in the city's central business districts.
Indeed, most recent scholarship contends that cities and suburbs are interdependent Ledebur and Barnes, , ; Savitch et al. Ihlanfeldt suggests five sources of interdependence: "First, the fortunes of suburbs may be tied to those of the central cities to the extent that outsiders' perceptions of the region are influenced by conditions prevailing within the core.
The attributes for evaluating geographic building blocks are well cited in the literature. These include: consistency, stability, scale and relevance. In Canada, there is no one geographic building block that satisfies all four of the above attributes. Currently, the geographic building block is the municipality. This geography is definitely relevant but it is not consistent or stable and scale could be better. As a consequence, both longitudinal and cross-sectional comparability can be compromised from time to time.
Currently, work is in progress examining the potential of using dissemination areas introduced as part of the Census as the geographic building block. On the surface this would appear to be a better choice in terms of consistency, stability and scale but falls far short of the mark with respect to relevance see Table 2.
However, the complexity of geographic association with the urban core may also increase as the building block decreases in size. The maps below present some initial research investigating the potential of using the dissemination area DA as the building block. The Calgary example, however, is quite different, with discontinuity and over and under bounding when assessed using the DA.
This illustrates the added complexity that can be associated with smaller geographic building blocks. The Statistical Area Classification SAC is recompiled every ten years following the decennial census and applied to the mid-decade census.
Updates to limits are done following the mid-decade census to reflect changes to CSDs and new entrants also are supported following each census with the delineation and calculation of urban core and total CA populations. Given the scale of the building block, this is a sufficient update cycle since too few CSDs would cross the threshold values to warrant more frequent updates.
This may not be the case if a DA building block were used. The concept in both countries focuses on the delineation of individual metropolitan areas with a core and a hinterland. Both are silent with respect to the explicit conceptualization of large metropolitan areas with multiple cores and metropolitan area integration to form metropolitan regions, although the United States and Canada to a lesser extent have incorporated criteria based on commuting data measures to define these links.
To provide a nationally consistent definition for collecting, tabulating and disseminating Federal statistics to measure economic and social conditions and thereby inform the nation. In the United States, the review process is open, visible and focused with documentation via the Federal Registry. In Canada, the process is open and documented via Statistics Canada reports but is not as visible or focused.
The large population nucleus, the form component, is modelled as the continuously urbanized or built-up area.
Both countries use the delineations from their most recent census to define. The integration of associated communities is the functional component modelled as a daily urban system using the relationship between place of residence and place of work often termed commuting data. In the United States, there is no explicit modelling to reflect the urban-rural continuum within the standard. In the United States, intra-metropolitan differentiation is part of the standard with criteria to define 'metropolitan divisions'.
Also, metropolitan areas can be combined to form what I see as 'metropolitan regions'. No similar criteria are included in Canada.
Counties, an administrative area and the primary division of most states, is used as the building block to form metropolitan areas and has consistently been the geography of choice for delineating metropolitan areas.
As described above in section 2. From the discussion in the reports released in the Federal Registry, it is apparent that the selection of an appropriate geographic building block is also of concern in the United States. It is of concern, and consequently an element repeatedly subject to review, because in both countries there is no single geographic area that can satisfy the attributes of the ideal geographic building block.
As a consequence, in both countries the unit selected represents a trade-off and in both countries the attribute of relevance reflecting a widely known administrative area with available data and historic inertia has greatly influenced the decision. It is also the element that contributes to the most difference in the delineation of metropolitan limits when comparing the delineations of individual metropolitan areas between the United States and Canada.
In terms of consistency, both the county and the CSD as an administrative area are not designed within their respective states and provinces to be nationally consistent in terms of geographic attributes. From the perspective of stability, change can and does occur to limits from time to time. Historically, major municipal restructuring moves have also occurred within provinces with a direct impact on stability of metropolitan delineations in Canada, which is a problem not encountered in the United States.
With more than metropolitan and micropolitan areas being delineated by counties, the ratio is about 3. However, because spatial contiguity is required when delineating CMAs and CAs , in practice the building block is the holding CSD usually the rural municipality or a ratio of about 17 to 1. A county in Canada is about ten times the size of a county in the United States. Recognition of the problem associated with the geographic building block used in both countries is fuelling the research into alternatives, such as the use of census tracts in the United States and dissemination areas in Canada see section 2.
The large population nucleus or core is defined according to the criteria used by the U. Bureau of the Census to define urban areas.
The criteria used delineate cores with a population density of 1, people per square mile ppsm and includes more-or-less contiguous territory with a density of at least ppsm with a total population of at least 2, The building block is the block or groups of blocks called block groups. Urban areas of at least 50, are called urbanized areas and urban areas with populations of at least 2, to 49, are called urban clusters. The urban core is defined according to the criteria used by Statistics Canada to define urban areas.
After accounting for metric measurement, the same density threshold is used in Canada but a total population of 1, is required. Urban areas from the previous census are retained and contiguous blocks that meet the density threshold are added. The approaches to define urban areas are very similar in many respects but there are also significant procedural differences.
The impact of these differences has not been quantified but in my opinion these differences would have a minimal impact on the delineation of metropolitan areas between the two countries with one possible exception. In the United States there are criteria that determine when an urbanized area should be split.
In Canada, large urban areas 50, or more retain their historic limits at the point of contact in a sense they are split by default and consequently continue to be urban cores for individual CMAs.
Given the limited extent of urbanization in Canada relative to that in the United States at the moment, this is not necessarily a source of great difference in the delineation of metropolitan areas between the two countries. However, if the American urban area criteria were applied in Canada there is the potential that the urban areas supporting the CMAs of Hamilton, Toronto and Oshawa could merge into one urban area and as result support one CMA.
Micropolitan area - an urban cluster with a population of at least 10, but less than 50, Census metropolitan area - an urban area with a population of at least 50, but a total population of at least , Census agglomeration - an urban area with a population of at least 10, but less than the CMA thresholds. Comparison of the population thresholds is interesting. For the Census, this was changed as described above and is consistent with the threshold required previously in the United States for urbanized areas.
As well, during the last formal review of the standard in the United States, one option presented was to raise the minimum population for a metropolitan area to , As noted above in section 2. Two of the six would have been added had the threshold remained at , So the impact of change has been to increase the number of CMAs for by four.
Perry, U. The central county or counties become the target for measuring commuting to define the hinterland of the metropolitan area.
The general approach used in the United States and Canada is again very similar. A noticeable difference is that in the United States the central county counties is explicitly identified and visible whereas in Canada it is not. Application of this criterion causes the impact of actual differences in the urban area delineations between the United States and Canada to be reduced when delineating metropolitan areas.
It is not possible to describe the impact at this time. In both countries, there has been discussion concerning data requirements to measure and delineate the extent of the hinterland. Despite the discussion, in both instances the conclusion has been that place of work and place of residence data commuting data is the single best measure: straightforward, consistent and national coverage via the census and public access.
The reverse threshold reflects the calibration made in relative to the CMA s and has been retained, given the lesser prominence of reverse commuting as a determining factor. Recent trends indicate however that reverse commuting is becoming more of a factor in the delineation of the hinterland and may warrant a revisit percentage of CSDs linked to urban core increased from 1.
The difference in commuting thresholds used is related to the difference in the size of the geographic building blocks. On the surface, it would seem that the forward commuting thresholds selected are equivalent, relative to the geographic building blocks used. However, a direct comparison of commuting percentage thresholds is complicated by the fact that the place of work question is different between the two countries.
Essentially, with a no fixed place of work option in the Canadian question, percentages calculated are on average 7. This could in turn increase the average out-commuting and require a reassessment of the percentage threshold. In both countries, spatial contiguity is a requirement when delineating the hinterland.
As well, the absolute magnitude of the commuting exchange is used to decide linkage in the event of an association with more than one urban area. CA identity is not retained except for identifying the urban core as a secondary urban core within the CMA. The procedures used in the United States to determine when merging of CBSAs should take place are consistent with metropolitan area hinterland rules and the rules for combining metropolitan areas.
The criteria used are the most appropriate, since merging results in the creation of a single CBSA. In Canada, the current criteria reflect a process that is in transition to define an increasingly more complex urban structure as evident by the changes in the methodology governing mergers and consolidation of metropolitan areas since the Census.
Metropolitan divisions are created to recognize the existence of multiple distinct employment and settlement centres in large urbanized areas 2. The employment interchange is the sum of the forward commuting percentage from the smaller CBSA to the larger and the reverse commuting percentage from the larger to the smaller.
The combined CBSAs retain individual recognition. The merging, metropolitan division and consolidation criteria in use in the United States reflect a scale of urbanization not generally present in Canada with the possible exception of the areas around Montreal, Toronto and Vancouver.
Consequently, the rules in the United States clearly differentiate between mergers, sub-centres within large metropolitan areas metropolitan divisions and consolidation combining of metropolitan areas reflective of metropolitan regions.
In Canada, the merger methodology is a blend of the merger and combination criteria applied in the United States. For these new CBSAs, hinterland delineation will be made using Census commuting data until These data will be used to define hinterlands for new and CBSAs. CBSAs are not reclassified between decennial censuses.
Recognition of new CMAs and CAs and adjustment for CSD boundary changes takes place every five years prior to next census based on data from the previous census. Calibration of hinterland limits occurs every 10 years for the mid-decade census using commuting data from the decennial census.
The approach is similar for all three entities and will include the names of principal cities in decreasing order of population size.
Combined CBSAs will also include state names, will be unique and may use a regional name if appropriate. Local opinion is sought for naming combined CBSAs. There are four criteria for defining principal cities. The other three criteria establish conditions for the second and third name and ensure that the names of additional places are significant places in terms of population size or as employment centres.
In general, this is also the name of the historic central CSD which, in most instances is also the most populous of the component CSDs. This convention has been used since the Census; however, a number of names that do not follow this convention have been grandfathered. Statistics Canada is carefully reassessing its approach to naming CMAs and CAs and is considering adopting criteria similar to the United States practice.
Use of the single name was favoured by Statistics Canada in the past because of its simplicity and stability over time no change as component CSD populations changed or component CSD structure was modified. Statistics Canada would like to minimize this confusion and is therefore considering a change to the naming convention as one way to improve upon the existing situation. Delineation methodology is the same as that for CMA since the Census. Use of population counts for this comparison is overly simplistic since the impact on the characteristics of the population or economic implications of areas added are not taken into account.
A block is an area formed by the intersection of roads and the boundaries of geographic areas used to disseminate census data. In preparing this comparison, I relied almost exclusively on the documentation provided by the Federal Registry concerning the review of the standard for defining metropolitan areas for the content and rules for the United States.
Comparison , by Richard A. Nadwodny and Henry A. Puderer Statistics Canada and Richard L. Forstall U. Bureau of the Census. Top of Page. The percentage of the resident labour force employed in primary activities was smaller than the national average. The population growth of the municipality over the period to exceeded the CMA growth rate.
If only one of the above but not both were met, then a municipality was still included if connected to the urban core via a major highway. Consistency means the geographic building block does not vary greatly in size, shape and compactness. Stability means consistency over time; i. Scale means the size of the geographic building block is appropriate to the measurement of the entity. When scaled properly for metropolitan delineation, over and under bounding should be minimal and longitudinal comparisons should not see sudden abrupt changes evident with the entry or exit of geographic building blocks when the building block is too large.
Associated with the attribute of scale are operational considerations such as data reliability, confidentiality and geographic complexity and aspects of contiguity and geographic integrity.
Relevance means the building block has inherent meaning and utility. Possession of this attribute is generally associated with administrative areas, which are in most instances understood and recognized and for which data from a variety of sources are available. Table 2. The employment interchange is the sum of the forward commuting percentage from the smaller county to the larger and the reverse commuting percentage from the larger to the smaller.
The differences in the methodologies for delineating metropolitan areas between the United States and Canada can be assessed from two perspectives: impact at the national level and impact at the level of an individual area. Urban areas are the start point in both countries for metropolitan area delineation. The methodologies employed are similar to the extent that they would for the most part identify the same urban areas if methodologies were exchanged discounting the minimum population requirements.
Therefore, at a national level of comparison the urban area delineation differences do not in my view contribute to major differences with respect to the delineation of metropolitan areas.
The extent of the urban areas delineated however may differ given the methodologies used. For the delineation of individual metropolitan areas, this difference may have an impact.
In Canada, historic urban areas are retained. This in effect splits urban areas that could be joined in the United States. With the relatively smaller degree of urbanization in Canada, the impact of this difference is cushioned and is probably restricted to the area around Toronto. The urban area thresholds for defining micropolitan and census agglomerations are the same 10, Therefore, taken together there is no impact on the comparability of national statistics.
However, the thresholds for metropolitan area creation are different and as a consequence comparability of data for the individual categories is affected.
This difference is easily adjusted to support comparability at the national level. Target core criteria are very similar. They are defined to support the calculation of forward and reverse commuting used to define the hinterland of metropolitan areas.
0コメント