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Modernizing Geographic Resources A BASIC TENET OF SURVEY RESEARCH is that the develop- ment of a sampling frame a listing of all units eligible for inclusion in the sample from which the sample is drawn is crucially important to the quality of the survey. Systematic biases or flaws in the frame may incluce serious errors of inference based on the survey results. Accorclingly, when considering a decennial census a survey of grant! scale it is difficult to overemphasize the importance of the underlying sampling frame. The quality of the acictress list to which questionnaires are mailed can lead to the omission or duplication of people or of entire housing units anct can hincler the goal of count- ing each resident once and only once within the precise geographic boundaries in which they belong. Hence, this panel stated in its first interim report that "the aciciress list may be the most important factor in determining the overall accuracy of a decennial census" (National Research Council, 2000:351. The "three-leggecl stool" strategy outlined by the Census Bureau in describing the early plans for the 2010 census includes attention to modernizing the Census Bureau's primary geographic resources: 39

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40 PLANNING THE 2010 CENSUS the Master Address File (MAF), the source of addresses not only for the decennial census, but also for the Census Bureau's numer- ous survey programs; and the Topologically Integrated Geographic Encoding and Ref- erencing System (TIGER), a database describing the myriad geographic boundaries that partition the United States. The specific set of activities that the Census Bureau has described to achieve this modernization is known as the MAF/TIGER Enhance- ments Program (MTEP). In terms of its spirit and nominal goal, the MAF/TIGER Enhancements Program may be of paramount im- portance in terms of its potential impact on the quality of the 2010 census. In this chapter, we review the MAF/TIGER Enhancements Pro- gram. As we will describe in detail, we support completion of the En- nancements ~ ro "ram, which should provide some necessary improve- ments to the TIGER database. However, we are concerned that the 1 . TO Enhancements Package does little to enhance to improve the MAF. More generally, the Census Bureau's strategy for dealing with the MAF shows signs of repeating costly and chaotic processes from MAF con- struction in the 2000 census. OVERVIEW: CURRENT STATE OF MAF AND TIGER Before we discuss the specific enhancements program that has been initiated by the Census Bureau, it is useful to first briefly review the nature and status of the two geographic systems addressed by the package to get a sense of exactly what is in need of enhancement. The Master Address File Purpose and Scope The Census Bureau's Master Address File (MAF) is, in essence, pre- cisely what the name implies; it is the Census Bureau's complete inven- tory of known living quarters in the United States and its island areas. The MAF contains a mailing address for those living quarters, if one

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MODERNIZING GEOGRAPHIC RESOURCES 41 exists. For housing units or living quarters without mail aciciresses, cle- scriptive aciciresses (e.g., "white house with brown shutters on left") may be coclect. The MAF also includes an intricate set of flags anct indicators that inclicate sources from which the aciciress was obtainer! anc! the time when it entered the MAF. In principle, the MAF is a constantly evolving en cl continually updated resource; the "snapshot" of the MAF that is extracted anct usect to conduct the decennial census is called the Decennial Master Aciciress File, or DMAF. Construction of the 2000 Census Master Address File The concept of a continuously maintained MAF is a relatively new one; in the 1990 anc! earlier censuses, aciciress lists were compiled from multiple sources prior to the census (most recently from commercial venclors) anc! were not retained after the census was complete. Follow- ing the 1990 census, the idea of maintaining the acictress list to sup- port not only the decennial census but also the Census Bureau's other survey programs took holcI. In part, writes Nash (2000:1), "a major impetus for this change was the unclercounts experienced in the 1990 anc! earlier decennial censuses, nearly a third of which was attributed to entirely missing housing units." An initial MAF was constructed using the city-style aciciresses1 on the Aciciress Control File (ACF) clevelopec! for the 1990 census (Hirschfelct, 2000~. To populate the MAF, the Census Bureau "clevisect a strategy of re- clunclancy using a variety of sources for aclclresses," thus "Eassuming] responsibility for developing a comprehensive, uncluplicatect file of act- clresses" (Nash, 2000:1~. Most prominent of the update sources were two that were endorsed by one of our predecessor Committee on Na- tional Statistics (CNSTAT) panels on the decennial census (National Research Council, 1995:5), which recommenclec! that the Census Bu- reau "clevelop cooperative arrangements with states en cl local govern- ments to develop an improver! master aciciress file" anc! that the U.S. 1A city-style address is one that can be specified by a numeric identifier (e.g., 305) in combination with a street name (e.g., Park Avenue), possibly with a specific subunit or apartment identifier. By comparison, non-city-style addresses are those that cannot be mapped to particular streets in this fashion, such as "Rural Route, Box 7" or a post office box.

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42 PLANNING THE 2010 CENSUS Postal Service be given "an expanclec! role" in census aciciress list oper- ations. Both these recommendations were significant in that they re- quirect legislative authority in orcler to operate within the prohibition on release of confidential data coclifiec! in U.S. Cocle Title 13, the legal authority for census operations.2 Congress granted this authority in the Census Aciciress List Improvement Act of 1994 (Public Law 103- 4301. The Delivery Sequence File One provision of the Census Aciciress List Improvement Act authorized the Census Bureau to enter into a data sharing arrangement with the U.S. Postal Service, under which the Postal Service woulct regularly share its Delivery Sequence File (DSF) with the Census Bureau.3 The DSF is the Postal Service's master list of all delivery point acictresses servect by postal carriers.4 The name of the file derives from the Postal Service-specific data coclec! for each recorc! along with a stanclarctizect acictress anct ZIP cocle: namely, cocles that inclicate how the aciciress is server! by mail delivery (e.g., carrier route anct the sequential orcler in which the acictress is serviced on that route). The DSF recorc! for a particular aciciress also includes a cocle for cleliv- ery type that is meant to indicate whether the address is business or resiclential. 2In Baldridge v. Shapiro, 455 U.S. 345 (1982), the U.S. Supreme Court ruled that the Census Bureau's "address list ... is part of the raw census data intended by Congress to be protected" under the confidentiality provisions of Title 13. Accord- ingly, the court concluded that the bureau's address list is not subject to disclosure under the Freedom of Information Act or under the discovery process in civil court proceedings. Specifically, the legislation text indicates that "the Postal Service shall provide to the Secretary of Commerce for use by the Bureau of the Census such address informa- tion, address-related information, and point of postal delivery information, including postal delivery codes, as may be determined by the Secretary to be appropriate for any census or survey being conducted by the Bureau of the Census. The provision of such information under this subsection shall be in accordance with such mutually agreeable terms and conditions, including reimbursability, as the Postal Service and the Secretary of Commerce shall deem appropriate." 4The list does not include general delivery addresses. Additional information on the DSF and commercial programs under which private companies are able to match their own address lists against the DSF can be found on the Postal Ser- vice Web site at http://www.usps.com/ncsc/addressservices/addressqualityservices/ deliverysequence.htm.

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MODERNIZING GEOGRAPHIC RESOURCES 43 Because the census is concluctec! largely through mailed ques- tionnaires most of which are subsequently mailed back the U.S. Postal Service is a crucially important conduit in the census process. Moreover, the Postal Service is a constant presence in the fielcI, servic- ing existing anct emerging routes on a claily basis. For these reasons, securing access to the DSF was a major accomplishment. The DSF is an uncloubtecily vital source of acictress information, albeit an incomplete one for census purposes since the list of mail delivery aciciresses is only a subset of the complete list of housing units in the United States. Mail delivery listings may also be incomplete in distinguishing multiple housing units within the same structure. The Postal Service began sharing the DSF with the Census Bureau in the micI-1990s. Currently, as part of the Census Bureau's ongoing Geographic Base Support Program, new versions of the DSF are shared with the Census Bureau twice per year en c! updates or "refreshes" to the MAF are made at those times. Local Update of Census Addresses The Census Aciciress List Im- provement Act of 1994 also authorized the secretary of commerce anct the Census Bureau to provide officials who are designated as census liaisons by a local unit of general purpose government with access to census aciciress information for the purpose of verifying the accuracy of the acictress information of the bureau for cen- sus and survey purposes. The act obligated the Census Bureau to "responcl to each recommen- elation made by a census liaison concerning the accuracy of address in- formation, including the determination (anc! reasons therefor) of the bureau regarding each such recommenclation." Put another way, the act permitted the Census Bureau to share with a local or tribal govern- ment the address data it had on file for that locality, for their review and upclate. To preserve Title 13 confidentiality, limits were placed on the infor- mation to be proviclect; the information to be ctisclosect to any particular locality was limited to aciciress information anc! to the set of aciciresses for that area. Ultimately, the acictress information would only be shared

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44 PLANNING THE 2010 CENSUS with local or tribal governments if they signet! an agreement to hole! the information as confidential anc! to dispose of it when finisher! with review. In August 1996, the Census Bureau initiated a program to ac- quire acictress list information from local governments. The Program for Aciciress List Supplementation (PALS) contacted local anc! tribal governments (along with regional planning agencies) anct solicited whatever lists of city-style aciciresses that they maintained for their jurisdictions. However, the Census Bureau quickly concluclect that the program was troubled; local aciciress lists were not necessarily in computer-reaclable format, anct then not formatted in such a way (in- clucling apartment and unit clesignators) as to match with the emerging coding system for MAF. More significantly, response by local govern- ments to an open-enclect query for local acictress lists ideally coclect to the appropriate census block was low. The program was officially ter- minatecl in September 1997 (U.S. Census Bureau, Geography Division, 1999~. The Census Bureau's next attempt at local geographic partnerships followoc! closer to the spirit of the Aciciress List Improvement Act by releasing parts of the Census Bureau's MAF for review rather than re- questing entire aciciress lists. The resulting program became known as the Local Upclate of Census Acictresses (LUCA), though it is also oc- casionally referred to as the Aciciress List Review Program. LUCA was concluctec! in two waves: LUCA 98. In 1998, local anct tribal governments in areas with predominantly city-style addresses were given the opportunity to review the Census Bureau's address list. Census Bureau car- tographers used blue lines to distinguish city-style address areas from non-city-style areas on the maps that defined eligibility for LUCA. Hence, LUCA 98 was said to target localities lying "insicle the blue line." LUCA 99. In 1999, attention turnec! to areas outside the "blue line," those with non-city-style acictresses.5 Local anct tribal gov- ernments were again offerec! the chance to review Census Bureau 5The "blue line" designating LUCA 98 and 99 areas was not constrained to follow borders of whole geographic locations, so many places and counties were eligible to participate in both waves of LUCA. In some localities, the blue line did not cleanly

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MODERNIZING GEOGRAPHIC RESOURCES 45 materials, but this time the offer was to review block-level counts of housing units rather than actual aciciresses. To participate in LUCA, local anct tribal governments were required to identify liaisons to handle the aciciress list materials anc! to execute an oath of confidentiality. Materials were sent to the local anct tribal gov- ernments, which hac! a specifier! time perioc! to analyze them anc! sub- mit any proposed changes. These changes were then reviewocl by the Census Bureau, which often opted to reject part or all of the localities' suggested aciclitions or cleletions to the aciciress list. An appeals process was set up uncler the auspices of the Office of Management anct Budget (OMB), giving local and tribal governments a final opportunity if they founct grounds to quarrel with the Census Bureau's judgments. The Working Group on LUCA commissioned jointly by this panel anct the Panel to Review the 2000 Census has concluctect an extensive review of the LUCA process from the participant's (local government) perspective (Working Group on LUCA, 2001~. Block Canvass In the 1990 anct earlier censuses, when acictress lists were not maintained from census to census but rather assembled be- fore the decennial enumeration, a complete fielc! canvass of the city- style acictresses in clesignatect mailout/mailback areas was a stanclarct- but costly operation. The Census Bureau had hoped to avoid a com- plete block canvass before the 2000 census; in introducing the Acictress List Improvement Act of 1994, U.S. Representative Thomas Sawyer ex- pressecl hope that "collection and verification of address information in primarily electronic format" from the Postal Service anc! local govern- ments "will greatly recluce the amount of precensus fielct canvassing," activity that he inclicatec! hac! proven "expensive anc! often inaccurate."6 Rather than a complete block canvass, the Census Bureau planned to target specific areas with coverage gaps anc! focus fielc! canvass activities on those areas. In spring and summer 1997, as a continuous MAF began to take shape, optimism about the completeness of DSF updates gave way to distinguish between city-style and non-city-style areas, causing frustration for some LUCA participants (Working Group on LUCA, 2001~. The process for delineating city-style-address areas should be refined for future LUCA-type programs. Representative Sawyer's remarks can be found in the Congressional Record for the 103rd Congress, page H10618 (October 3, 1994~.

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46 PLANNING THE 2010 CENSUS doubts, which were compounclec! by the failure of PALS to obtain acI- ciress information from local anc! tribal governments. Internal evalua- tions convinced the bureau that relying on DSF anct LUCA alone could leave gaps in MAF coverage; in particular, the bureau was concerned that "the DSF file missect too many acictresses for new construction anct was not updated at the same rate across all areas of the country" (Na- tional Research Council, 1999:39~. Accordingly, the Census Bureau opted to change course anc! con- cluct a full canvass of acictresses in mailout/mailback areas "in a manner similar to the traditional, blanket canvassing operations usec! in prior censuses." The bureau notect that the change would incur a large ex- pense but recognizing the bureau's concerns a previous CNSTAT panel "strongly enclorseLct] this change in plans" (National Research Council, 1999:25,39~. Plans for the complete block canvass overlapped with the emerg- ing plans for the LUCA program. The bureau originally planned for LUCA 98 to obtain feedback in early 1998, so that resulting changes to the MAF would be reacly for the block canvass in late 1999. However, delivery of MAF segments to most participating LUCA 98 localities was clelayoct. This led to a revisect plan that LUCA 98 changes would be compared to the MAF after block canvassing was complete. Further delays led to abandonment of a reconciliation operation in which ctis- crepancies between LUCA anc! block canvass observations woulc! have been reviewoct with localities; instead, localities received a list of ac- ceptec! en c! rejectee! aciciresses in LUCA's "final determination" phase and were given 30 clays to submit appeals to OMB's Census Aclclress List Appeals Office (Working Group on LUCA, 2001~. The TIGER Database Purpose and Scope The TIGER database is, effectively, a cartographic resource that cle- fines a complete digital map of the Unitec! States en c! its territories. It is intenclect to capture not only visible features the centerlines of streets, rivers, and railroacls, and the outlines of lakes, for instance but the myriac! political anc! administrative boundaries that may not corre- sponcl exactly with visible physical locales. Accorclingly, the TIGER

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MODERNIZING GEOGRAPHIC RESOURCES database includes the political geography of 3,232 counties or county- level equivalents, over 30,000 county subdivisions or minor civil divi- 47 signs, and over 20,000 named places, among other political units. Of the many types of geography defined by the TIGER database, the most important are the boundaries of census blocks. Census blocks are the smallest unit of geography for which basic population data are tabulated in the census, and so it is these fine-resolution data at the block level that are aggregated to form political and other adminis- trative boundaries. TIGER's primary function in census operations is geoco~ing, the matching of a given address or location to the census block in which it lies. Once a location has been matched to the cor- rect census block, its location in higher-level geographic aggregates constructed from blocks is also known, and so census returns may be properly tabulated by geographic unit. In addition to the geocoding function, the Census Bureau has relied on TIGER for three other major uses (O'Grady and Godwin, 2000; U.S. Census Bureau, 20011: geographic str?~ct?~re and relational analysis: how one geographic area relates to another, important for being able to aggregate small units like blocks into coherent higher-level aggregates; geographic definitions: serving as a repository for the current def- initions of geography levels recognized by the Census Bureau; and map production and dissemination: printing the maps used by cen- sus enumerators to carry out their assignments. . The full TIGER database maintained by the Census Bureau con- ta~ns point features along with linear features; in particular, points define the location of known housing units in areas without city-style addresses. However, most public exposure to the TIGER database comes via TIGER/Line files, a public excerpt of the TIGER database that contains only linear features such as roads, rails, and political boundaries (and, hence, not specific housing unit locations). The TIGER/Line files do contain complete street coverages with address ranges; it was the widespread availability of TIGER/Line files that facilitated the emergence and growth of the geographic information systems (GIS) industry.

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48 PLANNING THE 2010 CENSUS The TIGER database is one part of a larger TIGER system, which includes the support structure of hardware anc! software necessary for maintaining the database. When TIGER was initially clevelopect, the database was compiled in a unique anc! home-grown language cle- finect by the Census Bureau; various software programs to upclate the database anc! to produce maps were similarly written to accommodate the custom, internal database language TIGER uses. As we will discuss, the proposer! MAF/TIGER enhancements make changes in both the database anct system senses, improving the content of the database as well as overhauling the support machinery around it. How the TIGER Database Began The TIGER database was clevelopect by the Census Bureau, with assistance from the U.S. Geological Survey (USGS), to support the 1990 census. "TIGER began life as a patchwork quilt of data sources" (O'Gracly anc! Goc~win, 2000:6), two of which were primary. One of these sources was the GBF/DIME files used by the Census Bureau to clo aciciress matching to street segments in the 1980 census.7 The GBF/DIME files foreshaclowoct TIGER in that they applied topological principles in piecing together points, lines, and polygons (Hirschfelcl, 2000~; they also began the move toward including more than streets anc! roacis in census maps, acicling features such as water, rail, anc! invis- ible boundaries. However, these files were limited in scope, covering the urban centers of 276 metropolitan areas "less than 2 percent of the land area but 60 percent of the people in the Unitecl States" (Car- baugh and Marx, 1990~. To complete the geographic coverage of the nation, the aciciress reference information in the GBF/DIME files was merged with computer-coclect versions of the water anct transportation features clefinec! by the USGS series of 1:100,000-scale topographic maps (Marx, 1 986~. As O'Gracly and Goclwin (2000:4) note, "accuracy was crucial" when TIGER was first assembled "but only in a relational sense." "The coordinate information presented in the TIGER/Line files is proviclec! for statistical analysis purposes only," wrote Carbaugh anc! Marx (1990~; "it is only a graphic representation of ground truth." 7GBF/DIME stands for Geographic Base File/Dual Independent Map Encoding.

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MODERNIZING GEOGRAPHIC RESOURCES 49 Put another way, the priority in early TIGER was to achieve basic functionality for census purposes, which meant favoring relational accuracy Describing how geographic features relate to each other, such as whether census blocks are acljacent) over positional or locational accuracy (precise location of geographic features relative to a chosen stanciarcI). Hence, O'Gracly anc! Goc~win (2000:5-6) recall that the Census Bureau ctrew on properties of the USGS maps in publishing the following positional accuracy statement in the documentation for TIGER/Line files released in 1995: The positional accuracy varies with the source materials usecI, but at best meets the established National Map Accuracy stanclarcts (approximately +167 feet) where 1:100,000-scale maps from the USGS are the source. The Census Bureau cannot specify the accuracy of feature up- ciates aciclec! by its fielc! staff or of features clerivec! from the GBF/DIME-Files or other map sources. Thus, the level of positional accuracy in the 1995 TIGER/Line files is not suitable for high-precision measurement applications such as engineering problems, property transfers, or other uses that might require highly accurate measurements of the LEarth's] surface. In aciclition, the overall positional accuracy of early TIGER was lim- itect by shortcomings in the GBF/DIME files, which were also oriented towarc! relational accuracy. In particular, Census Bureau enumerators anct staff later founct that "hyctrographic features are not represented well" in TIGER database segments clerivec! from the GBF/DIME files (Rosenson, 2001:1~. Updates to TIGER Over the course of the 1990s, the TIGER database was updated using additional sources each with unique (ancl often unknown) levels of positional accuracy. Among those sources are the following programs that are likely to continue cluring anct after the MAF/TIGER Enhancements Program, although exactly how anct when the resulting information will be incorporated and how the programs might be restructured is as yet unspecifiecl:

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68 PLANNING THE 2010 CENSUS would benefit greatly from refocused staff effort. At least four major divisions within the Census Bureau (Geography, Field, Decennial Man- agement, and with the ACS Demographic Surveys) have a strong stake in the maintenance and use of the MAF. Given the legitimate (but sometimes competing) interests of the various divisions, it would be useful to vest responsibility for coordinating MAF improvement and research in one office with connections and the ability to work with all relevant divisions. Recommendation MAF-2: The Census Bureau should designate a resident expert to oversee the development and maintenance of the MAF as a housing unit inven- tory, with a focus on improving methods to designate, list, and update units. The bureau should give high priority to discussion and research, within the bureau and with experts outside the bureau, on the following: more effective means to define, list, and enumerate housing units and incorporate those changes into the housing unit inventory; more effective ways to define, list, and enumerate group quarters arrangements; sources of address duplication and possible reme- dies; and listing and enumeration in multi-unit structures. GEOGRAPHIC PARTNERSHIPS To its credit, the Census Bureau has recognized the importance of partnerships with local and tribal governments by designating their cre- ation and maintenance as Objective Three in the Enhancements Pro- gram. The Census Bureau's REP for the TIGER realignment of Ob- jective One makes this clear, noting that "the success of the Accuracy Improvement Project, and the continuous update of the information in MAF/TIGER, requires ongoing interaction between the Census Bu- reau and its federal, state, local, and tribal government geographic part- ners." To its cletriment, though, the Census Bureau has not provided

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MODERNIZING GEOGRAPHIC RESOURCES 69 clear indication of how partnerships woulc! work. While the panel ac- knowleciges that the funcis available for expanding anc! encouraging ge- ographic partnership options have been limitecl, the cryptic descriptions of Objective Three that we have received to this juncture clo not make it clear how the Census Bureau intends to involve local anct tribal partners in these programs. A major stated role for local anct tribal geographic partners is to contribute to Objective One to share their current GIS files with the Census Bureau to support realignment. In this matter, anct in past ge- ographic interactions such as LUCA, the Census Bureau often has per- ceivecl "partnership" as a one-sided exchange: "partners" expend re- sources anc! turn information over to the bureau. The principal reward to a local or tribal government for entering into this kind of partnership is definitely not trivial: the prospect of a more accurate census count. The Census Bureau is not a funcI-granting organization anc! hence can not directly subsidize local or tribal governments to improve anct sub- mit their geographical resources. That saicl, the Census Bureau should explore means of building partnerships that are true exchanges of infor- mation: for instance, giving census fielc! anc! regional staff an increased role in interacting with local anct tribal governments anct collecting in- formation updates. At the very least, steps shoulc! be taken to lessen the burclen of partnership: conducting LUCA-like acictress list reviews in electronic form with submissions via the Internet anc! (as mentioned earlier) coordinating the various geographic data collection programs so that localities are not being askoct for similar information in ctiffer- ent formats by different clivisions of the Census Bureau. The Census Bureau neects to articulate a plan for communication with localities that takes advantage of existing structures, including the State Data Center Network, the Fecleral-State Cooperative Program for Population Estimates, State/Regional Councils of Governments, anc! other local governmental entities. The role of the Census Regional Of- fice Geographic Coordinators relative to these entities anc! to Census Bureau headquarters neects to be spelled out. The ability and willingness of different governments to join forces with the Census Bureau vary widely. It is inevitable that tensions will arise when local efforts are differentially expressed across different ar- eas of the nation, whether such effort be clevotec! to mapping, to acI- ctress listing, or to the nurturing of partnerships. Different areas should receive equal treatment in the spirit of fairness, yet local interest, fea-

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70 PLANNING THE 2010 CENSUS sibility, anc! cost-effectiveness might well dictate otherwise. Moreover, geographic partnerships with local and tribal governments are useful to tap the knowledge anct expertise of those closest to the fielct, but those partnerships are not a panacea. Variation in geographic information sys- tems usage may impact the accuracy in local anct tribal government ge- ographic resources anc! coulc! in cases introduce error when mixed with census resources. In the interest of effectiveness, the successes anct failures of prior LUCA programs shoulc! be analyzer! in orcler to develop new commu- nity participation programs for 2010. Moreover, refinect evaluation of the 2000 address file by type of enumeration area, by dwelling type, by the contribution of geographic update programs like LUCA, and by re- gion of the country highlighting areas of the country where eliciting local anc! tribal information may be most beneficial is surely requirec! if the Census Bureau is going to maintain the MAF in a cost-effective manner in the years leacling to the 2010 census. The Census Bureau's future plans for LUCA and other partnerships programs should also include provision for evaluation of those very partnerships, not only to inform the effectiveness of local contributions from the census per- spective but also to provide feedback to participating local anc! tribal governments. Recommendation MAF-3: The Census Bureau and the Geography Division should move as expeditiously as possible to develop and describe plans for partnerships with state, local, and tribal governments in collecting address list and geographic information. Such plans should include a focus on adding incentive for localities to contribute data to the census effort, making it easier for localities and the bureau to exchange geographic in- formation. Plans for partnerships should clearly define benchmark standards for local data to be submitted to the bureau. THE KNOWLEDGE BASE FOR 2010: CURRENT AND FUTURE EVALUATION WORK A recurrent theme in our preceding remarks is that there is a strong need for empirical evaluation of the construction of the MAF for the

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MODERNIZING GEOGRAPHIC RESOURCES 71 2000 census. The foundation of the Census Bureau's evaluation studies along these lines is known as the MAF Extract. Related to the Decen- nial Master Address File the "snapshot" of the MAF that was used to generate census mailing labels and to monitor mail response the MAF Extract includes "flags" that indicate which of several sources contributed the address to the MAF. The MAF Extract also contains selected outcome measures, such as whether the address record was actually used in the 2000 census and whether it was tagged as a potential duplicate during the ad hoc duplicate screening program of early to mid-2000 (Nash, 20001. The MAF Extract has certain liabilities, chief among them that the system of flags used to indicate the source of an address does not constitute a true history of the address on the MAF. Other than rough temporal ordering of the input sources themselves, it is usually impos- sible to determine which source first contributed the address. Still, the extract is critical to answering key questions about the MAF-building process, and the panel continues to urge that the data resource be tapped for as much information as possible. Analyses of the extract should be conducted with respect to the type of enumeration area the address belonged to for the 2000 census (e.g., mailout/mailback or update/leave), as well as by geographic re- gion of the nation. The main objective of analysis of the MAF Extract is not to highlight how different areas of the country may have fared under various programs in place at the time. Areas of the country do differ, but knowledge of how they respond and interact with census activities is essential knowledge for the planning of future census pro- grams (see Question 6 below, for instance). Some key questions to address through Census 2000 evaluations are the following: 1. Why were addresses included in the MAF but not in the 2000 census? This question provides perspective for the others on this list and is a good starting place. 2. How useful were the DSF updates in the identification of new units, especially in high-growth areas of the nation? The goal is to examine how much of the newest housing was picked up in a timely fashion by the U.S. Postal Service. An-

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72 PLANNING THE 2010 CENSUS swers provide valuable clues about the effort the Census Bureau shoulc! put into other avenues (e.g., new construction program) as sources of information on new housing. 3. How effective were LUCA inputs relative to what was already known (or was promptly seen) in a DSF update? Of those con- tributions that can be cleterminect as "unique," how many gov- ernments were represented anc! what kind of housing clo these acictresses represent? While LUCA must be concluctec! in 2010, the resources the Cen- sus Bureau chooses to expend on it can vary dramatically. Also, the answer to this question can inform strategies for the LUCA program in 2010. 4. What were the original sources of acictress records that were cleletec! as duplicates in the act hoc duplicate identification anc! removal process concluctec! in 2000? Duplication that is tied to acictress listing anomalies can be recti- fiec! once the problems with duplicate aciciresses have been iclenti- fiect. Identifying the original contributing source of affected act- clresses is a prime means for doing that. 5. What were the original sources of aciciresses that were flagged as potential duplicates but later reinstated? This acictresses the hypothesis that some acictresses, originally consiclerec! as potential duplicates, were put back into the census in error. The Census Bureau already has an estimate of this number. By identifying the original sources of the aciciresses, the bureau will have valuable clues about what proclucect this problem and how to avoid it in the future. 6. What were the original sources of aciciresses for housing units where an interview was not obtained in nonresponse follow-up (NRFU) ? One hypothesis regarding the shortfall of long-form data in the 2000 census has to do with NRFU enumerators encoun- tering high levels of resistance from respondents who were being enumerated for the first time ever (some were there in 1990 but escaped cletection). Where did the addresses of these

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MODERNIZING GEOGRAPHIC RESOURCES 73 tough-to-enumerate units fall? (Of course, this is not the only hypothesis that coulc! explain problematic long-form ciata; it is almost certainly not the most likely hypothesis, either. But it is an intriguing question that shoulc! be aciciressable using internal Census Bureau data on the MAF.) 7. What were the original sources of acictresses for housing units when the housing unit was cleclarec! to be nonexistent or coulc! not be found in NRFU? NRFU enumerators hac! the option of entering cocles for "can- not locate," "cluplicate," and "nonresiclential," among others, as reasons for listing a unit as "nonexistent." Were these potential duplicates aciclec! back in? Were erroneous aciciresses brought in from LUCA that were not cletectect by the Census Bureau? Or were these aciciresses disproportionately from some other original source? 8. For cases where a unit was cleterminect not to exist in coverage improvement follow-up (CIFU; the final follow-up stage cluring the actual fielcting of the census), what was the original source of the aciciress? How many aciciresses were erroneously kept in the census and then cleletecl when the bureau went out to check in CIFU? The 1990 ACE, the initial 1997 DSF update, anc! block canvassing account for a very large percentage of all acictresses in the 2000 census in mailout/mailback areas. In absolute terms, these sources will clominate any original sources in a volume analysis. Nonetheless, normalizations are possible so that the Census Bureau can more properly quantify the real contributions of various inputs to those acictresses that were consict- erecl correct in the 2000 census. Most especially the effect, and perhaps differential effect, of LUCA programs neecis immediate attention. In this last assessment, account should be macle of the sometimes faulty nature of the LUCA program in the 1990s. timing anc! man accuracy problems among them. 1 ~ Completed Evaluations As part of the evaluation process for the 2000 census, an evaluation "topic report" on aciciress list development was scheclulec! for release

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74 PLANNING THE 2010 CENSUS in Tune 2003.~ This report will synthesize the results of individual evaluation reports related to the general topic. It is expected that the detailed individual reports will be released in conjunction with the topic report. Consistent with its previous recommendations, the panel urges the Census Bureau to continue to make evaluations related to address list development a priority and to actively incorporate them into 2010 planning, including the census field test in 2004. The panel has received access to a small number of individual topic evaluations that are not yet publicly available. These include: Assess- ment of Field Verification (Tenebaum, 2002~; The Address Listing Oper- ation and its Impact on the Master Address File (Ruhnke, 2002~; Block Canvassing Operation (Burcham, 2002~; Evaluation of the Local Update of Census Addresses 99 (LUCA 99) (Owens, 2002~; and List/Enumerate (Zajac, 2002~. Though they are not yet publicly available, we do wish to offer some comment on them to help guide future evaluation work. Field Verification In field verification, enumerators visited the locations of units with returned questionnaires lacking an assigned census ID number, to ver- ify existence. These responses came from the Be Counted Program, from Telephone Questionnaire Assistance, and other alternative re- sponse modes. Some 885,000 cases were subject to this verification step. About half of them were coded as valid; about a third of them were coded as deletes; the remainder as duplicates. Of particular interest: more than half of the addresses that had been deleted in two or more previous operations were coded as valid addresses. Tenebaum (2002:11) suggests "that the Bureau may need to conduct additional research into the source of the double deletes with a mail return to . . . . . . . . . try to determine why they were deleted In two or more previous operations." We would like to see this research, with an emphasis on address histories and especially original sources, and with further detail on geographic locations and multi-unit dwellings. Some of the geographic detail is here by regional census office and by type of local Spas of the end of July 2003, the report had not yet been made publicly available. Lithe Be Counted program allowed respondents who felt that they had been missed in the mailout of census forms to pick up a census form from public offices and submit it.

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MODERNIZING GEOGRAPHIC RESOURCES 75 census office; some data are also available on the multi-unit aciciresses involvec! in fielc! verification. Address Listing Operation The Aciciress Listing Operation (Ruhnke, 2002113 appears to have been quite successful, if not efficient. It is noteworthy that among some 22 million acictresses aciclect to the MAF by this operation, 99 percent of them were deliverable to the DMAF anc! 43 percent of them matched to acictresses iclentifiect as residential on or before the September 1998 DSF. However, the performance of Aciciress Listing in handling multi- unit structures is hindered by a flaw in the definition of the MAF vari- able containing the number of separate housing units at a basic street acictress (BSA). Specifically, all non-city-style acictresses which consti- tute at least 14 percent of the cases aciclec! by aciciress listing are auto- matically consiclerect single units. Although the evaluation report con- tains some geographic clisaggregation Breakdowns by state), much of the report has little bearing on the questions we have listed above. Block Canvassing Operation The Block Canvassing Operation (Burcham, 2002) playocl a big role in improving the coverage of aciciresses on the MAF anc! in improving the associated geococting, presumably at considerable expense. Block canvassing proclucec! 6.4 million aciclitions (some 30 percent of which were corrections or completions of acictresses already on the MAF anct some 35 percent of which were in multi-unit BSAs). Among the 6.4 million acictitions, 78 percent of them were valict acictresses for the 2000 census. There were 5.1 million cleletions (of which 48 percent were in multi-unit BSAs) anct 24 percent of them turned out to be valict act- ciresses for the 2000 census. Burcham (2002) provides some mention Tithe Address Listing Operation was used to build an initial address list for geo- graphic areas of the country that were to be enumerated using update/leave method- ology. Between fuly 1998 and May 1999, census field staff went door-to-door in these designated areas, making a list of mailing addresses and locations as they went along. The results from this operation, Address Listing, were then used to assign work during the actual census. In 2000, census field enumerators visited these sites to leave cen- sus questionnaires and logged MAF updates they encountered (hence the update/leave terminology).

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76 PLANNING THE 2010 CENSUS of particular areas a large number of LUCA 98 cleletes occurrec! in Cook County, Illinois, clustering of acicis anc! cleletes was fount! in Ver- mont, anct there were many nonresidential cleletes in Los Angeles, for example where local information appears to resolve outlying results. These case studies provide useful lessons for future reference; a good clear of information is broken clown by state. The report cloes touch on our Question 3 about LUCA but acicts little information central to it. LUCA 99 Reports by the Working Group on LUCA (2001) anct the National Research Council (2001a) provide further insight into levels of LUCA participation by size of government and geographic location. However, only the Census Bureau evaluations can provide a picture of LUCA effectiveness by key variables. Owens (2002) provides some information pertinent to Question 3, of which the following is perhaps of most interest to the panel. Par- ticipation rates were higher for larger governmental bodies; 2.2 million LUCA 99 addresses were subject to recanvass with about 76 percent being verified, 18 percent corrected, anct 6 percent cleletect; recanvass- ing itself aciclec! 328,000 aciciresses; some group quarters may have been aclclecl through LUCA 99 and the subsequent recanvassing; some of this information is broken clown by state. List/Enumerate List/Enumerate (Zajac, 2002) aciclec! about 390,000 aciciresses to the MAF in sparsely populated areas of the country, more than 99 percent of which were incluclec! in the 2000 census; a rough estimate of cost per acictress is $50. A fair amount of information is broken clown by state. Evaluation here cloes not provide many answers to questions posec! earlier. General Assessment MAF evaluation work is required if the Census Bureau is to assess targeting methods for the ultimate goal: "to accurately identify local ar- eas with potential MAF/TIGER coverage/quality problems," especially as it concerns the 2004 tests (Waite, 2002~. In this vein, some of the

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MODERNIZING GEOGRAPHIC RESOURCES . 77 Census Bureau's forthcoming evaluation studies are of particular im- portance. One of these is the Housing Unit Coverage Study (Barrett et al., 2001) that clears with erroneous enumerations by MAF source; we suggest that the Census Bureau focus on erroneous enumerations by type (e.g., cluplicates). The evaluation reports proviclec! to us generally give volumes and rates of acicts/cleletes that, when of interest, lack sufficient detail to be of use in guicling cost-effective strategies for targeting areas for coverage and acictress list improvement. Waite (2002) mentions the relative stability of the aciciress list in the 2000 census as a tool for . MAF targeting we certainly endorse this thought, but we have not seen what is planned in this regard. Evaluations clo not, as yet, yield much information on the aciclec! cost and benefit of programs. This information is surely crucial to the clecision-making process during the present clecacle. Evaluations and presentations still fall short of alleviating our fear that the process of maintaining and updating the MAF in the near future becomes the default one of acquiring DSFs on some regular schedule, with augmentation from LUCA programs after fielc! verification on a neecI-to-know basis. We have seen too few signs that cost and effectiveness of various acictress sources are unclerstooct on the basis of what transpired in the late 1990s. Such unclerstancling remains an issue of the highest possible priority. Recommendation MAF-4: Consistent with the panel's related recommendations on evaluation studies and the crucial importance of address list issues in conducting the census, the Census Bureau should: 1. strive to fully exploit the information on address sources contained in the MAF Extract in complet- ing 2000 census evaluations and assessing causes of duplicate and omitted housing units; and 2. build the capability for timely and accurate evalu- ation into the revised MAF/TIGER data architec- ture, including better ways to code address source histories and to output data sets for independent evaluation purposes.

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