Reengineering the 2010 Census Risks and Challenges (2004) / Chapter Skim
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II Issues of Census Design
II Issues of Census Design
3 Modernizing Geographic Resources
Pages 55-102
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Part I} Issues of Census Design
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As the pane! stated in its first interim report, "the address list may be the most important factor in determining the overall accuracy of a decennial census" (National Research Council, 2000a: 354.
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However, the MAF/TIGER Enhancements Program is oriented overwhelmingly toward TIGER and does little to enhance to improve the MAF. The Census Bureau's strategy for dealing with the MAF is, to an unfortunate degree, little more than routine maintenance seemingly deferring active attention to the MAF until a complete block canvass very late in the census cycle (thus repeating a costly operation from 2000 that had been implemented as an eleventh-hour fix)
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From page 59... ...
Construction of the 2000 Census Master Address File The concept of a continuously maintained MAF is a relatively new one; in the 1990 and earlier censuses, address lists were compiled from multiple sources prior to the census (e.g., lists were purchased from commercial vendors) and were not retained after the census was complete.
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The Delivery Sequence File One provision of the Census Address List Improvement Act authorized the Census Bureau to enter into a data-sharing arrangement with the U.S. Postal Service, HA city-style address is one that can be specified by a numeric identifier (e.g., 305)
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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 U.S.
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Ultimately, the address information would be shared with local or tribal governments onIv if they signed an agreement to keep it confidential and to dispose of it when finished with review. In August 1996, the Census Bureau initiated a program to acquire address list information from local governments.
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counts of housing units rather than actual addresses. To participate in LUCA, local and tribal governments were required to identify liaisons who would handle the address list materials and take an oath of confidentiality.
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Even large local governments with complete local geographic information files found it difficult to meet the turnaround time required for submission of addresses to the Census Bureau. The problem may have been compounded for local governments with less-developed geographic resources and in cases where manual review of address lists was the best or only available option; indeed, tight timelines combined with the requisite investment of resources may have dissuaded some governments from participation.
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Representative Thomas Sawyer expressed hope that "collection and verification of address information In pr~marily electronic format" from the Postal Service and local governments "will greatly reduce the amount of precensus field canvassing," an activity that he indicated had proven "expensive and often inaccurate."6 Rather than a complete block canvass, the Census Bureau planned to target specific areas with coverage gaps and focus field canvass activities on those areas. In spring and summer 1997, as a continuous MAE began to take shape, optimism about the completeness of DSF updates gave way to doubts when it also became clear that PALS was not proving an effective means to obtain address information from local and tribal governments.
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Further delays led to abandonment of a reconciliation operation in which discrepancies between LUCA and block canvass observations would have been reviewed with localities; instead, localities received a list of accepted and rejected addresses in LUCA's "final determination" phase and were given 30 days to submit appeals to OMB's address list appeals office (Working Group on LUCA, 2001~. 3-A.2 The TIGER Database The TIGER database is, effectively, a cartographic resource that defines a complete digital map of the United States and its territories.
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The Census Bureau's full TIGER database contains both point and line features; in particular, points define the location of known housing units in areas without city-style addresses. However, most public exposure to TIGER comes via TIGEIVLine files, a public excerpt of the TIGER database that contains only linear features such as roads, rails, and political boundaries (not specific housing unit locations)
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As O'Grady and Godwin (2000) note, "accuracy was crucial" when TIGER was first assembled "but only in a relational sense." "The coordinate information presented in the TIGEIVLine files is provided for statistical analysis purposes only," wrote Carbaugh and Marx (19901; "it is only a graphic representation of ground truth." 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 adjacent)
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Among those sources are the following programs that are likely to continue during and after the MAF/TIGER Enhancements Program, although exactly how and when the resulting information will be incorporated and how the programs might be restructured is as yet unspecified: . Boundary and Annexation Survey (BASJ: an ongoing voluntary survey in which TIGER-generated boundary maps are sent to local and tribal governments for review and update.
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Though some DEX capability had been developed and selected local geographic files were obtained prior to the 2000 census, active TIGER updating using DEX was deferred during the actual conduct of the 2000 census. The Need to Modernize The development of TIGER is a milestone of which the Census Bureau should be extremely proud.
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As a result, it has not been possible to directly update TIGER's street coverages using the GIS files updated and maintained by local and tribal governments. The Census Bureau's unique role in delineating census blocks the base units that are aggregated to form most political districtsand ongoing programs such as the Boundary and Annexation Survey (BAS)
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, which has also been known as the American Community Survey Coverage Program; and 5. implement periodic evaluation activities and expand quality metrics.
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This general framework provides great flexibility for the Census Bureau and its contractor to implement the TIGER update; at present, however, to the extent that plans have been shared with the panel, this flexibility translates into little specificity. The Census Bureau has established a cartographic accuracy standard for the realigned TIGER database: 7.6 meters CE95, meaning that, for a sample of control points measured on the ground and the corresponding locations in the geographic database, at least 95 percent of the database-recorded points should lie within a 7.6-meter radius of the corresponding ground-recorded points.
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Other potential means of collecting the geographic information include buying commercially available GIS files or using field staff to collect GPS trace data while driving or walking streets. It is as yet unclear which of these (or other)
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3-B.2 Objective Two: Modern Processing Environment Objective Two of the Enhancements Program targets TIGER in the systems sense, modernizing the structure of the database. The current homegrown TIGER system suffers from key limitat~ons, prominent among them the inability to directly link with commercial GIS packages (and hence local and tribal GIS files maintained using those packages)
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We discuss the tasks to be accomplished under Objective Two in greater detail in Section 6-C. 3-B.3 Objective Three: Geographic Partnerships Objective Three acknowledges the crucial role of state, local, and tribal governments in maintaining geographic resources, not only for the TIGER realignment of Objective One but for continued update of the MAE, as in the LUCA program.
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does not effectiveIv identify the existence or location of new housing units; and J J 2. provide address list (and street)
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The anticipated level of effort that the Census Bureau expects to expend on Objective Five is roughly equivalent during each of the fiscal years 2003-2010. 3-B.6 Update on Enhancements Program Progress The Census Bureau's goal for fiscal 2003 was to complete Objective One TIGER realignment for 250 counties.
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3-C ASSESSMENT OF GEOGRAPHIC MODERNIZATION EFFORTS 3-C. ~ Locational Accuracy of TIGER Problems with the positional accuracy of TIGER have been apparent to the Census Bureau and its users for some time; anecdotal experiences of problems with TIGER representations were reported by field enumerators during the 2000 census and in feedback from local and tribal governments that participated in LUCA (Working Group on LUCA, 20014.
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generally came closest to true locations. The Census Bureau's Geography Division also conducted pilot experiments comparing TIGER coordinates for small geographic samples to a combination of GPS coordinates and commercially available cartographic databases (U.S.
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That said, concerns about the work remain, and the plausibility of the Census Bureau's ambitious realignment timetable would be bolstered considerably through attention to the following: · a detailed work plan, including the order in which counties will be initially updated; · realistic estimates of the number of available state and local GIS files that meet, in part or in full, the Census Bureau's chosen positional accuracy standard for the realigned TIGER; · a clear Nan for the evaluation of initia]
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We hope and trust that this approach has been rectified as the Bureau has developed procedures with its contractor; the Bureau noted in its update of Enhancements Program progress that "Harris is required to align TIGER road features exactly to the source data (which, again, must meet or exceed the 7.6 meter accuracy standard) as well as maintain TIGER's topological integrity" (U.S.
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emphatically believes that Objective Five is a crucial part of the Enhancements Program and should lead to the development of general quality metrics for all of the Census Bureau's geographic programs. However, with respect to progress on Objective Five, two comments must be made.
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3-D.1 Current Plans for MAF Updates for 2010 The Census Bureau argues that the combination of three activities "the ongoing MAF/TIGER updating using the Delivery Sequence File, CAUS, and enhancements included in the pro
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The backbone of the Census Bureau's update strategy is the twice-yearly "refresh" that comes from the Postal Service's Delivery Sequence File. These regular updates are considered to be part of the Bureau's Geographic Support Base Program, not the MAF/TIGER Enhancements Program.
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It is unclear how much time and manpower ACS managers will commit to the side work of the address listing given the ambitious timetable of ACS data collection. · Unclear/unspecified mechanism for targeting areas for update.
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Our supposition was that the Census Bureau would pursue targeted block canvassing identifying selected geographic areas with sufficiently fast growth or other characteristics to warrant a thorough precensus address list check. In responding to the interim report at our September 2003 meeting, the Census Bureau expressed surprise at this statement, maintaining that a full block canvass was always part of the Census Bureau's 2010 plan.
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Still, having the 2000 MAF in hand does not give license to defer active address list updating to 2009. We believe and sincerely hope that the sentence is a misstatement; indeed, in later text, the baseline design document strikes a more reasonable note, pledging "work with USPS, local, and tribal partners" through the decade and saying that, "whenever we identify new housing units or those that no longer exist, we will update our files" (Angueira, 2003b:44.
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However, it is unclear whether empirical evidence supports the assertion that block canvassing is more likely than other operations to correct addresses. Creating the impression that, near the end of the decade, the Census Bureau will make a major deployment of field staff to perform block canvassing because local input on address information is somehow less trustworthy may only serve to further hinder participation by local and tribal authorities in Census Bureau activities.
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. A complete and accurate Master Address File is critical not only to the success of the 2010 census but also to the effective implementation of the American Community Survey, the other household surveys conducted by the Census Bureau, and the 2008 dress rehearsal.
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More effective definitions of housing units and methods to obtain accurate address listings for structures containing multiple housing units, as it is not sufficient to know only the address or geographic coordinates of the structure location; 3. Detail on the temporal sequencing and adequacy of address updates from the U.S.
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We reiterate a recommendation from our second interim report (National Research Council, 2003a:Rec. MAF-24: Recommendation 3.2: The Census Bureau should create and staff a position to oversee the development and maintenance of the MAF as a housing unit inventory, with a focus on improving methods to designate, list, and update units.
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Postal Service, including but not limited to further work on "undeliverable as addressed" items from the 2000 census, assessment of the address coverage quality of the Delivery Sequence File (DSF) , and possibilities for more accurate translation of post office box listings anti other DSF entries to street atl~lresses anti geographic coordinates.
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Postal Service's Delivery Sequence File by geographic area or type. 3-E.5 Plan Local Geographic Partnerships and Implement Early To its credit, the Census Bureau has recognized the importance of partnerships with local and tribal governments by designating their creation and maintenance as Objective Three of the Enhancements Program.
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At the very least, steps should be taken to lessen the burden of partnership on the local and tribal governments for example, by conducting LUCA-like address list reviews electronically with submissions via the Internet, and coordinating the various geographic data collection programs so that localities are not asked for similar information in different formats by different divisions of the Census Bureau. The Census Bureau needs to articulate a plan for communication with localities that takes advantage of existing structures, including the State Data Center Network, the Federal-State Cooperative Program for Population Estimates, state and regional councils of governments, and other local governmental entities.
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Moreover, although geographic partnerships with local and tribal governments can be useful to tap the knowledge and expertise of those closest to the field, variations in GIS usage may affect the accuracy of local and tribal government geographic resources and may introduce errors when combined with census resources. In the interest of effectiveness, we recommend careful analysis of the successes and failures of prior LUCA programs in order to properly conduct future community participation programs.
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Likewise, we believe that the Census Bureau's decision to proceed with a full block canvass should also be justified with empirical evidence. We do not suggest that block canvassing is an idea that lacks merit.
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is also concerned that reliance on a block canvass may send unfortunate mixed messages about the relative quality of the address list needed for different purposes that special operations are needed to derive an address list of presumably higher quality than that needed for the Census Bureau's other surveys and, particularly, the ACS. We therefore recommend: Recommendation 3.6: The Census Bureau should evaluate the necessity of its plans to conduct a complete block canvass shortly before the 2010 census.
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Based on the 2000 census Decennial Master Address File the "snapshot" of the MAF used to generate census mailing labels and to monitor mad! response the MAF Extract includes "flags" that indicate which of several sources contributed the address to the MAF.
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Duplication related to address listing anomalies can be rectified once the specific problems with the duplicate addresses have been identified. Identifying the original source of the affected addresses is a prime means for doing that.
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or most likely hypothesis to explain problematic long-form data, but the question warrants attention and the Census Bureau's MAF Extract data may be able to provide useful information.) What were the original sources of addresses for housing units that were subsequently declared nonexistent or were not found in NRFU?
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702 ~~ ~ 2070 ^~: ~^ 4~ Ages sus evaluations, 0H gaps in knowledge remaining Mom the 2000 census evaluations, and assess causes of duplicate and omitted housing unity and build the capability far timely and accurate address evaluation into the revised TIGER data architecture, including hefter ways to code address source histories and to format data sets far independent evaluation.
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