Planning the 2010 Census Second Interim Report (2003) / Chapter Skim
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3. Modernizing Geographic Resources
3. Modernizing Geographic Resources
Pages 39-78
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From page 39... ...
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 counting 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.
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From page 40... ...
In this chapter, we review the MAF/TIGER Enhancements Program. As we will describe in detail, we support completion of the Ennancements ~ ro "ram, which should provide some necessary improvements to the TIGER database.
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From page 41... ...
, "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)
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From page 42... ...
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)
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From page 43... ...
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.
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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.
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From page 45... ...
to execute an oath of confidentiality. Materials were sent to the local anct tribal governments, which hac!
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From page 46... ...
tribal governments. Internal evaluations 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" (National Research Council, 1999:39~.
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From page 47... ...
. The full TIGER database maintained by the Census Bureau conta~ns point features along with linear features; in particular, points define the location of known housing units in areas without city-style addresses.
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From page 48... ...
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.
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From page 49... ...
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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From page 50... ...
tribal governments, in which TIGERgeneratect boundary maps are sent to governments for review anct update · MAT Geocoding Office Resolution (MAFGOR) : a program in which city-style acictress records from the Postal Service Delivery Sequence File (DSF)
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From page 51... ...
tribal governments. The Census Bureau's unique role in delineating census blocks the base units that are aggregated to form most political districts anc!
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From page 52... ...
local anc! tribal governments to extenct from a TIGER/Line base, realigning features when errors are fount!
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From page 53... ...
anc! maintained by local or tribal governments, commercial GIS files, or digital orthophotography/aerial photography.
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tribal governments must be established in orcler to accomplish Objective One realignment anc! change detection.
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, the estimated level of effort devoted to Objective One exceeds that given the other objectives combined. Objective Two: Modern Processing Environment Objective Two of the Enhancements Program targets TIGER in the systems sense, modernizing the structure of the database.
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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 MAF, as in the LUCA program. Subtasks of Objective Three identified by the Census Bureau are as follows: 1.
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From page 57... ...
Postal Service's Delivery Sequence File (DSF) does not effectively identify the existence or location of new housing units; 2.
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From page 58... ...
anct programs involving direct use of local anct tribal geographic files (e.g., DEX) generally came closest to true locations.
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From page 59... ...
An accurately aligned TIGER, faithful to polygonal features such as municipal boundaries, can be passed along to localities and made available on the Internet, thereby allowing local anc! tribal entities the opportunity to report changes macle to both linear (e.g., roact anct railroad anct polygonal features (e.g., administrative borders collected by the Bounclary en cl Annexation Survey)
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From page 60... ...
with specifications for the positional accuracy required of local anc! tribal GIS files; anc!
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From page 61... ...
An architecturebasect approach coorctinatect with the rest of the Census Bureau may acict structure to the system of inputs anct outputs to MAF anct TIGER, including the information that is requested from state, local, anc! tribal governments.
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From page 62... ...
It is essential, in our view, that quality assessment through such metrics be an ongoing and well-timed process so that updating of the database achieves the apparent goal: information in MAF/TIGER maintained to a currency of 1 year or less at all times. WEAKNESS: ENHANCING THE MAF The MAF/TIGER Enhancements Program will make improvements to TIGER that are necessary, given known problems with TIGER accuracy.
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From page 63... ...
The backbone of the Census Bureau's upclate strategy is the twiceyearly "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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From page 64... ...
.1° · Limitation of DSF to mail delivery population. Again, by clefinition, the DSF is intenclect to document mail delivery acictresses~ which is not equivalent to the complete list of housing units in the Unitecl States.
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From page 65... ...
· ACS workload management. It is unclear how much time en cl manpower ACS managers will commit to sicle work on acictress listing given the ambitious timetable of ACS data collection.
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From page 66... ...
its evaluation work on the construction of the 2000 MAF, since that work is crucial to bolstering the case for the 2010 acictress upclate strategy. Recommendation MAF-1: In articulating the MAF/ TIGER Enhancements Program and defining its strategy for updating the MAF for the 2010 census, the Census Bureau should provide clearer details on how the MAF/ TIGER Enhancements Program and other geographic programs will add missing addresses, remove duplicate addresses, and generally correct the Master Address File, independent of benefits derived from being crossreferenced to an updated TIGER database.
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From page 67... ...
Particularly problematic are small multi-unit structures, facilities, and homes with multiple residents but whose divisions into subhousing units is not obvious. A realigned TIGER database may offer a precise location for a structure an aerial photograph may confirm a structure's existence or point to the construction of a new one but that added precision is ultimately of little use if the address roster of subunits within the structure is unknown or inaccurate.
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From page 68... ...
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 remedies; 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 creation and maintenance as Objective Three in the Enhancements Program.
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From page 69... ...
anc! regional staff an increased role in interacting with local anct tribal governments anct collecting information updates.
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From page 70... ...
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 systems usage may impact the accuracy in local anct tribal government geographic resources anc!
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From page 71... ...
Related to the Decennial 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.
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From page 72... ...
6. What were the original sources of aciciresses for housing units where an interview was not obtained in nonresponse follow-up (NRFU)
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From page 73... ...
7. What were the original sources of acictresses for housing units when the housing unit was cleclarec!
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From page 74... ...
These include: Assessment of Field Verification (Tenebaum, 2002~; The Address Listing Operation 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~.
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From page 75... ...
However, the performance of Aciciress Listing in handling multiunit structures is hindered by a flaw in the definition of the MAF variable containing the number of separate housing units at a basic street acictress (BSA)
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From page 76... ...
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 areas with potential MAF/TIGER coverage/quality problems," especially as it concerns the 2004 tests (Waite, 2002~.
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From page 77... ...
strive to fully exploit the information on address sources contained in the MAF Extract in completing 2000 census evaluations and assessing causes of duplicate and omitted housing units; and 2. build the capability for timely and accurate evaluation into the revised MAF/TIGER data architecture, including better ways to code address source histories and to output data sets for independent evaluation purposes.
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