Guidelines for Using Rural-Urban Classification Systems for Public Health Assessment

Transcription

1 Guidelines for Using Rural-Urban Classification Systems for Public Health Assessment Revision Date: February 5, 2009 Primary Contact: Asnake Hailu, Dr.PH, Rural Health Epidemiologist, Office of Community Health Systems Secondary Contact: Juliet VanEenwyk, Ph.D., State Epidemiologist for Non-Infectious Conditions Purpose What is new, and how does this affect public health assessment? Why a guideline on rural-urban classification systems? How rural is Washington State? What systems are commonly used to classify rural-urban character? County, Census Tract and Zip Code definitions Choosing the right classification system The Rural-Urban Commuting Area (RUCA) system: a good choice A four-tier consolidation of the RUCA system at the sub-county level Washington State classifications by county Trend analysis Other considerations when making rural urban comparisons Guidelines: A recap List of Acronyms References Appendix 1: Comparison of public health indicators using 2001 and 2008 four-tiered consolidations of RUCA codes Appendix 2: RUCA code definitions Appendix 3: Comparison of the 1990 and 2000 census tract boundaries Purpose The Assessment Operations Group in the Washington State Department of Health (DOH) coordinates the development of guidelines related to data development and use to promote good professional practice among staff involved in assessment activities within DOH and in Local Health Jurisdictions in Washington. While the guidelines are intended for audiences of differing levels of training related to data development and use, they assume a basic knowledge of epidemiology and biostatistics. They are not intended to recreate basic texts and other sources of information, but rather they focus on issues commonly encountered in public health practice and where applicable refer to issues unique to Washington State. What is new, and how does this affect public health assessment? The 2008 guidelines for rural-urban classification systems have two major changes from the 2001 version of these guidelines. The Washington State Office of Community Health Systems no longer recommends using the Dominant Rural-Urban Commuting Area (RUCA) classification system for Washington State Washington State Department of Health, Revised February

2 counties. In 2003, several other county-based systems with methodologies compatible with those used to develop the Dominant RUCA Codes became available nationally (Table 4). As described below, DOH recommends using the, and Core- Based Statistical Area classifications used by the US Office of Management and Budget (OMB) for county-level classification. As described below, the current guidelines adopt a four-tiered consolidation of RUCA codes derived from a seven-tiered consolidation by the Washington, Wyoming, Alaska, Montana, and Idaho (WWAMI) Rural Health Research Center. This four-tiered consolidation differs from that recommended in the 2001 guideline. This change transfers two census tracts in Chelan and Whatcom Counties from Small Town and Isolated Rural to Sub-Urban and one census tract in Whitman County from Large Rural Town to Small Town and Isolated Rural. Overall, the change affects less than 1% (2000 Census data) of Washington residents. Results from analysis of health indicators with old and new four-tiered RUCA consolidations did not show significant changes. (See Appendix 1) Why a guideline on rural-urban classification systems? The Washington State Office of Community Health Systems has documented differences in health status and related risk and protective factors between residents of rural and urban Washington. Analysts looking at rural health disparities must choose from several classification systems which change over time. Guidelines are useful for promoting consistency, comparability and best practice among statewide analyses that look at rural health. Local public health assessments and measurement of performance standards also benefit from consistent classification systems to compare local health data to areas with similar population and settlement patterns. These guidelines do not cover the use of rural-urban classification schemes for determining eligibility for state or federal assistance programs. See How Many Agencies does it Take to Define Rural? for a summary of eligibility criteria for rurally-targeted programs. Also, see Washington State Office of Financial Management for references to population density in Washington law. How rural is Washington State? In 2008, between 13% and 27% of Washington s residents lived in areas classified as rural depending on the classification method used. For example, nine Washington counties are classified as rural using the Washington State Office of Financial Management (OFM) designations and as metropolitan using nationally developed systems. This underscores that there is no gold standard for the defining features of rural areas or a single best theoretical basis for classifying rural areas. Some classification systems measure rurality on the basis of population density, others by economic or commuting connections. The choice of the geographic unit (county, census tract, or ZIP code) for analysis introduces further variation. Regardless of the classification system, Washington is a predominantly urban state and is becoming more urbanized over time. Analysts comparing health indicators in rural and urban areas should be aware that rates may be worse in rural compared to urban areas, but with very few exceptions, the total numbers affected are much higher in urban areas. What systems are commonly used to classify rural-urban character? The first rural-urban classification system, developed in 1874 by the US Census Bureau, defined rural as the population of a county living outside of cities or towns with 8,000 or more inhabitants. That population threshold was changed to 2,500 in The US Census Bureau now defines urban as all territory, population, and housing units in Urbanized Areas and Urban Clusters with Washington State Department of Health, Revised February

3 2,500 or more persons. This definition is based on a very fine level of geography, the census block group. Urbanized areas and urban clusters are contiguous built-up areas with a population density of more than 1,000 persons per square mile. Currently, an Urbanized Area is a contiguous set of block groups with a population of more than 50,000. An Urban Cluster is a contiguous set of block groups with populations of between 2,500 and 49,999. The remaining areas are Rural Areas. Most rural-urban classification systems are based on these definitions. The US Census Bureau s most recent revision of these definitions in 2002 resulted in a larger enlargement of Urbanized Areas than would have happened by population increase alone. Figure 1 shows how the boundaries of Urbanized Areas changed in Washington. Details about the methodological changes in 2002 and a list of urbanized areas are available by the Census Bureau. Early systems tended to be binary in nature, classifying counties as urban or rural. These binary systems gave way to more complex county coding systems such as Rural-Urban Continuum Codes (RUCC) that recognize differences in size and the importance of issues like economic influence. With advances in computing power and geographic information systems in the 1990s, sub-county classifications systems, most notably RUCA system, were developed. For more information see Ricketts et al. (1998) and USDA Economic Research Service: Rural Classifications. Washington State Department of Health, Revised February

4 Table 1: Commonly Used Rural-Urban Classification Systems Classification System Urbanized Areas, Urban Clusters, and Rural Areas, and Core Based Statistical Area (Previously and Non-) Developer # of Classes Geographic Unit US Bureau of the Census 3 Census Block Group US Office of Management and Budget Rural-Urban Continuum Codes US Department of Agriculture - Economic Research Service Urban Influence Codes US Department of Agriculture - Economic Research Service Rural Economically Distressed Counties Rural Urban Commuting Areas (RUCA) * Year published in the Federal Register. Washington State Office of Financial Management US Health Resources and Services Administration - Federal Office of Rural Health Policy /US Department of Agriculture Economic Research Service First Developed (Latest Revision) (2002*) 3 County 1940s (2003*) 9 County Mid 1970s (2003) 9 County Mid 1990s (2003) 2 County 1990s (2008) 10 Census Tract or ZIP Code Late 1990s (2005) County, census tract and ZIP code definitions Many classification systems (for example,,, and Core-based Statistical Areas, Figure 2) use county-level geographic aggregation, based on population density and dominant economic commuting pattern. Figure 2:,, and Non-Core Counties in 2003 Whatcom San Juan Skagit Okanogan Ferry Stevens Pend Oreille Island Clallam Snohomish Jefferson Kitsap King Chelan Douglas Lincoln Spokane Mason Grays Harbor Thurston Pierce Kittitas Grant Adams Whitman Pacific Lewis Yakima Franklin Garfield Columbia Wahkiakum Core-Based Statistical Area Cowlitz Clark Skamania Klickitat Benton Walla Walla Asotin Washington State Department of Health, Revised February

5 Using county-based classification systems is attractive in that county lines tend to be stable over time and many health, social and economic indicators are readily available for counties. However, these county-level systems tend to classify the residents of urban or sub-urban centers in large rural counties as rural. Nationally, 11% of residents of counties, as defined by the OMB, are classified as rural by the US Census Bureau s block group classifications and 7% of the residents of Non- Counties are classified as urban (Hart et al., 2005). Compared to county-level classification systems, sub-county classification systems, while often more precise, are more complex. For example, census tract and ZIP code boundaries change more frequently than do county boundaries, adding to the complexity of classification systems based on census tracts or ZIP codes. Choosing the right classification system Analysts should consider three main factors when choosing a rural-urban classification scheme. 1) At what unit of geography are the health event and population data available? The decision of which rural-urban classification scheme to use may be driven by the level of geocoding in the health dataset, as well as the availability of population denominators, if the analyst needs to generate rates, Although many health datasets include ZIP or county codes, the complete street address required for geo-coding to census tract is less commonly available and when available, may have more missing values. Population estimates, especially estimates by age, sex and year, are commonly available at the county level. Estimates at smaller levels of geography are less consistently available. (See Guidelines for Population Denominators and Rates) 2) Is there special interest in a particular level of rural or urban geography? Some county classifications (e.g., Urban Influence Codes) distinguish between counties with large and small urban areas. However, these classification schemes generally do not account for residential suburban areas often found on the fringes of urban counties located across the county border. Subcounty classification schemes, (e.g., RUCA codes), are more effective at identifying the bedroom communities adjacent to, but in different counties than the urban core. The analyst might be interested in differentiating more remote from less remote rural areas. Classification systems with larger spectrums of rurality, such as Rural-Urban Continuum Codes, Urban Influence Codes or RUCA codes, differentiate remote rural areas from less remote rural areas. Thus, they are appropriate for rural to rural comparisons. 3) Is comparability and reproducibility of the findings or methods for other states or the nation important? In some cases, the value of adopting a more widely used classification scheme outweighs the value of choosing a scheme that might yield higher precision or otherwise be more suited to answering a specific question. Nationally, the OMB s,, and Core-Based Statistical Area system for county classification and the RUCA sub-county classification are the two most widely used rural classification systems. The Rural-Urban Commuting Area (RUCA) system: a good choice For most analyses, the Washington State Office of Community Health Systems recommends the RUCA system. The US Departments of Agriculture and Health and Human Services and the WWAMI Rural Health Research Center, originally developed this system in the late 1990s. It is the only system available at the census tract or ZIP code levels. The RUCA system is currently considered the state of the art, and is used widely. The RUCA system is more precise than county-based alternatives, since it uses smaller geographic units. The RUCA system is a ten-tiered classification system that uses US Census Bureau definitions of Urbanized Areas and Urban Clusters and commuting relationships at the census tract level as the basic building blocks. The primary (largest) and secondary (second largest) commuting flows to core areas are identified using the most recently available commuting data, the 2000 US Census Washington State Department of Health, Revised February

6 for the latest version of RUCA. Strongly linked tracts are those where the primary commuting flow to a core area is greater than 30% of commuting trips. Weakly linked tracts are those where the largest flow to a core area is 10-30%. Isolated rural areas are those with no town greater than 2,500 where the primary commuting flow is local. This yields the following scheme: Table 2: Rural Urban Commuting Area (RUCA) Classification System: Ten Primary Tiers General Classification (Urban) (50,000 or more) (Large Rural Town) (10,000-49,999) Small Rural Town (2,500 9,999) Isolated Rural (under 2,500) Core Area Codes High Commuting Flow (more than 30%) Codes Low Commuting Flow (Between 10-29%) Codes The ten codes are sub-divided into 33 secondary codes which can be consolidated or combined in several different ways. See Appendix 2 for a listing of the secondary codes. Washington State RUCA codes using census tract geography are mapped in Figure 3. A 2004 ZIP code approximation of the 2000 RUCA codes developed by the WWAMI Rural Health Research Center is mapped in Figure 4. The ZIP code approximation is less accurate than the census tract version. ZIP codes do not uniformly correspond with census blocks as do the census Washington State Department of Health, Revised February

7 tracts. A listing of 2006 ZIP code approximations of the RUCA codes is available at DOH Healthcare Access and Research page. More information on the RUCA system is available at the WWAMI Rural Health Research Center. A four-tier consolidation of the RUCA system at the sub-county level Many datasets do not have sufficient sample size to support analysis using a ten-tiered classification system. For general descriptive analyses where sub-county data are available, we suggest a four-tiered consolidation based on secondary codes that identify the general character of an area. Urban Core: contiguous built-up areas of 50,000 persons or more. These areas correspond to US Census Bureau s Urbanized Areas. Sub-Urban: areas, often in Counties, with high commuting flows to Urban Cores (for example Eatonville in Pierce County). These areas also include all other areas where 30%-49% of the population commutes to Urban Cores for work. Large Rural Town: towns with populations between 10,000 and 49,999 and surrounding rural areas with 10% or more primary commuting flows to these towns, as well as secondary commuting flows of 10% or more to Urban Cores. Small Town and Isolated Rural Areas: towns with populations below 10,000 and their surrounding commuter areas and other isolated rural areas with more than one hour driving distance to a nearest city. Washington State Department of Health, Revised February

8 Table 3 provides the four-level consolidation recommended by the Washington State Office of Community Health Systems. This consolidation is based on the WWAMI Rural Health Research Center s seven-tiered classification system. WWAMI s own four-tiered classification collapses all of urban into one urban category, and splits rural among three additional categories. (See We recommend the consolidation in Table 3, because large proportions of Washington residents live in urban and sub-urban areas, making analyses with these designations informative. This Guideline defines the urban core and other urban found in the seven-tiered consolidation as Urban Core and Sub-Urban, respectively. Large Rural Town combines large rural core and other large rural from the seven-tiered classification. Small Town and Isolated Rural Areas comprise the remaining three rural categories from WWAMI s seven-tiered classification: small rural core, other small rural, and isolated rural. Table 3: Four-Tier Consolidation of Secondary RUCA Codes Class Tier Secondary RUCA Codes Urban Core 1 1.0, 1.1 Sub-Urban 2 2.0, 2.1, 3.0, 4.1, 5.1, 7.1, 8.1, 10.1 Large Rural Town 3 4.0, 4.2, 5.0, 5.2, 6.0, 6.1 Small Town/Isolated Rural 4 7.0, 7.2, 7.3, 7.4, 8.0, 8.2, 8.3, 8.4, 9.0, 9.1, 9.2, 10.0, 10.2, 10.3, 10.4, 10.5, 10.6 As with the full set of RUCA codes, the census tract version of the four-tiered consolidation (Figure 5) allows more precise classification than a similar consolidation done with the ZIP code RUCA approximations (Figure 6), since the ZIP code boundaries do not always coincide with census tract or county boundaries. But the ZIP code approximation of RUCA codes can be used with several public health datasets that use ZIP code as the smallest geographic level. Data analysts need to be aware that ZIP codes change over time. These changes can result in misclassification. Washington State Department of Health, Revised February

9 Washington State Department of Health, Revised February

10 Washington State classifications by county Table 4 shows classifications of Washington s counties based on the county-level classification systems described below. The Washington State Office of Community Health Systems recommends using,, and Core-Based Statistical Area classification used by the OMB, because this is the most widely used classification system nationally. It is more precise than two-level classification systems while having the advantage of a small number of categories allowing collapsing over sufficient numbers for analysis., and Core-Based Statistical Areas: The OMB has used this national classification system since the 1940s for statistical reporting and allocating funds. Until recently, this system classified counties as or Non-. In 2003, the US Census Bureau that develops the system, divided Non- counties into and Core-Based-Statistical Areas. At the same time, the US Census Bureau increased the commuting threshold for tying in outlying areas from 15% to 25%. Currently, counties with cities or urbanized areas over 50,000 are classified as. Counties with urban clusters of 10,000 to 49,999 persons are classified as. In addition, any county in which at least 50% of the population resides in an Urbanized Area are designated as or. Outlying counties meeting a complex set of conditions based on commuting patterns and population density are also designated either as or. All other areas are designated a Core-Based Statistical Area. The US Census Bureau maintains the most recent national list and technical documentation. Figure 2 shows a map of Washington counties classified by this system. Rural-Urban Continuum Codes (RUCC): The US Department of Agriculture (USDA) developed the RUCC system, also known as the Beale code system, in the mid-1970s. It was a forerunner of the Urban Influence Codes and present RUCA system. The system uses, and Core-Based Statistical Area classifications as a starting point. counties are classified into three population categories. Non- counties are classified into six categories based on total population in US Census Bureau s Urbanized Areas. Non- communities are further classified by adjacency to counties and commuting patterns. This system better differentiates between central and fringe metropolitan areas than the OMB s three-level system. The most recent update was in For more information and to download codes see Urban Influence Codes: The USDA developed a 12-level classification scheme in the mid-1990s to emphasize the tendency of economic systems to centralize around very large metropolitan counties. counties are classified as Large (population of at least one million) or Small (population less than one million). counties are classified by adjacency to Large or Small counties. Counties in a Core- Based Statistical Area are classified by their adjacency to and counties and whether they contain a town of 2,500. This system was most recently updated in For more information and to download codes see Other Variations: Several other classification systems that apply to subsets of areas, activities, or populations may be useful for rural public health assessment. In 1999, the Washington State Legislature passed a law defining rural distressed counties as those with population densities of fewer than one hundred persons per square mile. Other classification systems include multiple definitions of frontier areas and county-based typologies of primary economic activity. For additional information related to county classification, see. Washington State Department of Health, Revised February

11 Table 4: Commonly Used Rural Urban Classifications for Washington Counties County Adams Asotin Benton Chelan Clallam Clark Columbia Cowlitz Douglas Ferry Franklin Garfield Grant Grays Harbor Island Jefferson King Kitsap Kittitas Klickitat Lewis Lincoln 2003,, 2003 Rural Urban Core Continuum Codes Based (USDA) Statistical Area (OMB) Mason Okanogan Small Rural Small Small Small Large Rural Not Adjacent Large Small Rural Small Small Isolated Rural Not Adjacent Small Isolated Rural Large Rural Large Rural Large Rural Small Rural Large Small Small Rural Small Rural Large Rural Isolated Rural Small Rural Small Rural 2003 Urban Influence Codes (USDA) 2008 Rural Distressed (OFM) 2008 Population (OFM) with town of at least 2,500 residents Rural 17,800 1 million residents Rural 21,400 1 million residents Rural 165,500 1 million residents Rural 72,100 not adjacent to a metro area Rural 69,200 Large-in a metro area with at least 1 million residents or more Urban 424,200 with town of at least 2,500 residents Rural 4,100 1 million residents Rural 99,000 1 million residents Rural 37,000 Noncore not adjacent to a metro/micro area and does not contain a town of at least 2,500 residents Rural 7,700 1 million residents Rural 70,200 and does not contain a town of at least 2,500 residents Rural 2,300 area adjacent to a small metro area Rural 84,600 area adjacent to a small metro area Rural 70,900 adjacent to a large metro area Urban 79,300 with town of at least 2,500 residents Rural 28,800 Large-in a metro area with at least 1 million residents or more Urban 1,884,200 1 million residents Urban 246,800 adjacent to a large metro area Rural 39,400 with town of at least 2,500 residents Rural 20,100 area adjacent to a small metro area Rural 74,700 and does not contain a town of at least 2,500 residents Rural 10,400 area adjacent to a small metro area Rural 56,300 with town of at least 2,500 residents Rural 40,100 Washington State Department of Health, Revised February

12 Pacific Pend Oreille Pierce San Juan Skagit Skamania Small Rural Not Isolated Rural Large Isolated Rural Not Adjacent Small Large Noncore adjacent to micro area and contains a town of at least 2,500 residents Rural 21,800 and does not contain a town of at least 2,500 residents Rural 12,800 Large-in a metro area with at least 1 million residents or more Urban 805,400 Noncore not adjacent to a metro/micro area and does not contain a town of at least 2,500 residents Rural 16,100 1 million residents Rural 117,500 Large-in a metro area with at least 1 million residents or more Rural 10,700 Snohomish Large Large-in a metro area with at least 1 million residents or more Urban 696,600 Spokane Stevens Thurston Wahkiakum Walla Walla Whatcom Whitman Yakima Mid-size Small Rural Small Isolated Rural Large Rural Small Large Rural Small 1 million residents Urban 459,000 with town of at least 2,500 residents Rural 43,700 1 million residents Urban 245,300 and does not contain a town of at least 2,500 residents Rural 4,100 area adjacent to a small metro area Rural 58,600 1 million residents Rural 191,000 area adjacent to a small metro area Rural 43,000 1 million residents Rural 235,900 Trend analysis Four major changes occurred between the 1990 and 2000 US Censuses which complicate attempts to track trends in rural-urban disparities. 1) Census tract boundaries were realigned. An overlay of 1990 and 2000 Washington Census Tracts (Appendix 3) shows that the realignments are particularly noticeable in the rapidly growing areas surrounding major population centers. 2) As discussed in What Systems are commonly used to classify the rural urban character?, the US Census Bureau revised the methodology for establishing Urbanized Areas and Urban Clusters in These changes expanded the boundaries of Urbanized Areas. Figure 1 compares 1990 and 2000 Census Urbanized Areas in Washington. It is unclear how much of the change between 1990 and 2000 is the result of the new method and how much is due to population growth, because the new method has not been applied to 1990 data. Because most rural classification schemes use the Urbanized Area definition as a starting point, this change has had broad ramifications. Chief among them is that comparisons over time are difficult to interpret. 3) As described in Washington State classifications by county, the US Census Bureau revised the methods for establishing and Non- areas in 2003 This change also affected Urban Influence Codes and RUCC which are tied to the definitions. Washington State Department of Health, Revised February

13 4) The rules for classifying census tracts for RUCA codes were revised in The primary change was raising the lower threshold for establishing commuting relationships from 5% to 10%. The primary effect of this change was to increase populations and areas classified as rural. Rural-urban trends between 1990 and 2000 are obscured due to the magnitude and complexity of these changes and the absence of bridging methods built on 1990 and 2000 US Censuses. Recommendations for trend analysis: Because classification systems built on the 1990 and 2000 US Censuses are not comparable, the Washington State Office of Community Health Systems recommends beginning trend analysis in 1995 and using classification systems based on methods that incorporate 2000 US Census data. o The author should note that the comparison is based on classifications at a point in time (2000). Some areas, particularly those with large population change, may be misclassified or would change classification if more complete data were available. An assessment of population change within classifications across the study years might help interpret findings. If the data analyst needs to assess trends prior to 1995 using systems based on 1990 and 2000 US Censuses, we recommend that the analyst o o Explore the significance of classification changes before treating the data as a continuous series. Clearly show on trend lines or charts where major methodological changes occurred. o Interpret trends with caution. Other considerations when making rural-urban comparisons in Washington Because the proportion of elderly residents in rural areas is higher than in urban areas, the analyst should consider age-adjustment for age-related public health indicators. (See Rates guideline for a discussion of age-adjustment.) Analysts should also keep in mind that, in general, the residents of rural Washington have lower incomes, have completed fewer years of formal education, and have differing racial and ethnic backgrounds than those in other areas. Differences in health status between rural and urban Washingtonians may reflect these underlying differences in demographics. There are also regional variations in the demographic structure of rural Washington. The Hispanic population has a strong presence in Central Washington, and the tribal population has a strong presence in Northeast Washington. Northwest Washington (San Juan and Island Counties) are more Caucasian and affluent. Walla Walla, Whitman, and Kittitas Counties host universities which have significant influences on both age and poverty structure. Island County has a very large military presence. Sensitivity analyses excluding these outlier counties may be warranted in analyses examining health indicators or population demographics that may be inordinately influenced by these populations. Guidelines: A recap When making rural-urban comparisons definitions matter. It is essential that analysts document the classification system, including explaining why the system was selected, and discussing its strengths, limitations and possible biases. This information needs to be easily accessible to users to help them interpret findings and compare across studies. Washington State Department of Health, Revised February

14 If data are available at the census tract or ZIP code level, use the RUCA system, collapsing the ten RUCA codes into four categories as in Table 3. If data are only available at the county level, use, and Core-Based Statistical Area classifications. Changes over time may be best assessed using 2000 rural-urban designations and 1995 as a starting point. Trend analyses using classification systems built on the 1990 and 2000 US Censuses are not recommended because of methodological changes and the absence of bridging data between census years. If long term comparisons are attempted, o o County-level classifications are more stable than those based on smaller geographies. Bias due to changes in methods and geographic boundaries needs to be discussed. Rural-urban health differences may reflect underlying differences in demographics. In general, rural-urban comparisons of public health indicators should be age-adjusted, as the proportion of elderly residents in rural areas is higher than in urban areas. Analysts should also keep in mind that, in general, the residents of rural Washington have lower incomes, have completed fewer years of formal education, and have differing racial and ethnic backgrounds than those in other areas. Acronyms DOH OFM OMB RUCA RUCC USDA WWAMI Washington State Department of Health Washington State Office of Financial Management US Office of Management and Budget Rural-Urban Commuting Areas Rural-Urban Continuum Codes US Department of Agriculture Washington, Wyoming, Alaska, Montana, and Idaho References Hart LG, Larson E, and Lishner GM. Rural definitions for health policy and research. American Journal of Public Health; 95:7, 2005 July, pp Ricketts TC, Johnson-Webb KD, Taylor P. Rural definitions for health policy makers. Bethesda (MD): Dept. of Health and Human Services (US), Federal Office of Rural Health Policy; 1998 July. Washington State Department of Health, Revised February

15 Appendix 1 Comparison of public health indicators using four-tiered consolidations of Rural Urban Commuting Area (RUCA) codes recommended in the 2001 and 2008 versions of the Washington State Department of Health's Guidelines for Using Rural-Urban Classification Systems for Public Health Assessment Indicator Percent of adults ages 18 and over who report having health insurance, Percent of adults age 18 and over who report a usual source of health care, Percent of adults age 18 and over who report ever having a heart attact, angina, or coronary heart disease, 2004&2006 Percent of women age 50 and over who report breast cancer screening, 2004&2006 Percent of adults age 50 and over who report colorectal cancer screening, 2004&2006 Percent of women age 18 and over who report cervical cancer screening, 2004&2006 Percent of adults age 18 and over who report having visited a dentist in past year, 2004&2006 Urban Core %(CI)* 2001 four-tiered RUCA consolidation 2008 four-tiered RUCA consolidation Sub-Urban %(CI) Large Rural Town %(CI) Small Town/Isolated Rural %(CI) Urban Core %(CI) Sub-Urban %(CI) Large Rural Town %(CI) Small Town/Isolated Rural %(CI) 83 (± <1) 83 (± 2) 80 (± 2) 73 (± 2) 83 (± <1) 83 (± 1) 80 (± 2) 73 (± 2) 78 (± <1) 80 (± 1) 78 (± 1) 75 (± 1) 78 (± <1) 80 (± 1) 78 (± 1) 75 (± 1) 5.4 (± <1) 6.1 (± <1) 5.6 (± <1) 6.4 (± <1) 5.4 (± <1) 6.1 (± <1) 5.5 (± <1) 6.4 (± <1) 80 (± 1) 77 (± 3) 81(± 2) 74 (± 2) 80 (± 1) 77 (± 3) 81(± 2) 74 (± 2) 63 (± 1) 61 (± 2) 57(± 2) 58 (± 2) 63 (± 1) 61 (± 2) 57(± 2) 58 (± 2) 79 (± <1) 78 (± 2) 78(± 2) 76 (± 2) 79 (± <1) 78 (± 2) 78(± 2) 76 (± 2) 73 (± <1) 69 (± 2) 66 (± 2) 65 (± 2) 73 (± <1) 69 (± 2) 66 (± 2) 65 (± 2) * Age-adjusted percent Source: Washington State, Department of Health, BRFSS Dataset, compiled by Washington State Department of Health Community Health Systems Office Washington State Department of Health, Revised February

16 Appendix 2 Rural-Urban Commuting Area (RUCA) Code Definitions: Version area core: primary flow within an urbanized area (UA) 1.0 No additional code 1.1 Secondary flow 30% to 49% to a larger UA 2 area high commuting: primary flow 30% or more to a UA 2.0 No additional code 2.1 Secondary flow 30% to 49% to a larger UA 3 area low commuting: primary flow 10% to 30% to a UA 3.0 No additional code 4 area core: primary flow within an Urban Cluster of 10,000 to 49,999 (large UC) 4.0 No additional code 4.1 Secondary flow 30% to 49% to a UA 4.2 Secondary flow 10% to 29% to a UA 5 high commuting: primary flow 30% or more to a large UC 5.0 No additional code 5.1 Secondary flow 30% to 49% to a UA 5.2 Secondary flow 10% to 29% to a UA 6 low commuting: primary flow 10% to 30% to a large UC 6.0 No additional code 6.1 Secondary flow 10% to 29% to a UA UA=Urbanized Area UC=Urban Cluster 7 Small rural town core: primary flow within an Urban Cluster of 2,500 to 9,999 (small UC) 7.0 No additional code 7.1 Secondary flow 30% to 49% to a UA 7.2 Secondary flow 30% to 49% to a large UC 7.3 Secondary flow 10% to 29% to a UA 7.4 Secondary flow 10% to 29% to a large UC 8 Small rural town high commuting: primary flow 30% or more to a small UC 8.0 No additional code 8.1 Secondary flow 30% to 49% to a UA 8.2 Secondary flow 30% to 49% to a large UC 8.3 Secondary flow 10% to 29% to a UA 8.4 Secondary flow 10% to 29% to a large UC 9 Small rural town low commuting: primary flow 10% to 30% to a small UC 9.0 No additional code 9.1 Secondary flow 10% to 29% to a UA 9.2 Secondary flow 10% to 29% to a large UC 10 Isolated small rural areas: primary flow to a tract outside a UA or UC 10.0 No additional code 10.1 Secondary flow 30% to 49% to a UA 10.2 Secondary flow 30% to 49% to a large UC 10.3 Secondary flow 30% to 49% to a small UC 10.4 Secondary flow 10% to 29% to a UA 10.5 Secondary flow 10% to 29% to a large UC 10.6 Secondary flow 10% to 29% to a small UC Source: University of Washington WWAMI Rural Research Center Washington State Department of Health, Revised February

17 Appendix 3 Census Tract Changes in 2000 Census Comparison of the 1990 and 2000 Census Tracts Washington State Department of Health, Revised February