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OCR for page 39
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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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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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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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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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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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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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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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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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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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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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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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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Representative terms from entire chapter:
geographic resources
