The goal of PSAP is to produce meaningful statistical geographies for data users while
maintaining consistent statistical geography nationwide.
The Census Bureau classifies two types of geographies: legal and statistical geography.
Statistical geographies are areas defined solely for data collection, tabulation,
dissemination, and analysis. That said, we recognize that statistical geographies—census
tracts, especially—are used in a variety of federal programs. Though it is tempting to
want to change boundaries to meet the needs of a particular program, please be aware that
a change that may have a positive effect for one program may have a negative impact on
another. It is better to maintain the statistical objectivity and comparability of areas,
updating areas to meet the general analytical needs of as many data users as possible.
Statistical Geography boundaries generally follow permanent, visible features that are
identifiable in the field.
* Follow visible features whenever possible.
* Use significant/major features on landscape.
* Align to legal geography where a relationship has been established and is unlikely
to change over the decade due to changes in the legal entity’s boundary.
* Follow legal conjoint boundaries, where applicable. For example, given the stability
of city and town boundaries in the Northeast, census tract boundaries may align with the
boundaries of a city or town. With census designated places, it is preferable to align
with a city boundary than to leave a small gap between the two places.
* Reflect current land use patterns where possible.
Boundaries should not:
* Cut through housing and other buildings.
* Include “zig-zags” and sharp angles for no purpose.
* Group disparate land use types for no reason.
* Make use of less prominent features when a more significant feature could be used.
The following criteria apply to census tracts in the United States, Puerto Rico, and the
* Census tracts must not cross county or state boundaries.
* Census tracts must cover the entire land and water area of a county.
* Census tracts must comprise a reasonably compact and contiguous land area, with a
* Exceptions to the compactness requirement might include areas with unique
population groups, land uses, or settlement patterns, such as coastal communities, a
community ringing a lakeshore, valley settlements, and commercial and industrial
development along a linear transportation route defined as a special use census tract.
* Census tract boundaries should follow visible and identifiable features.
* Census tracts must have a basic numeric identifier composed of no more than four
digits and may have a two-digit decimal suffix.
The Census Bureau may modify and, if necessary, reject any proposals for census tracts
that do not meet the published criteria.
In addition, the Census Bureau reserves the right to modify the boundaries and attributes
of census tracts as needed to meet the published criteria and/or maintain geographic
relationships before or after the final tabulation geography is set for the 2020 Census.
Census tracts must meet specific population and housing unit thresholds outlined on the
next slide Census Tract Thresholds.
The following criteria apply to block groups in the United States, including federally
recognized American Indian reservations (AIRs) and off-reservation trust lands (ORTLs),
Puerto Rico, and the Island Areas:
* Must not cross census tract boundaries.
* Must cover the entire land and water area of each census tract.
* Must comprise a reasonably compact and contiguous land area, with a few exceptions.
* As with census tracts, exceptions might include areas with unique population
groups, land uses, or settlement patterns, such as coastal communities, a community
ringing a lakeshore, valley settlements, and commercial and industrial development along a
linear transportation route defined as a special use block group.
* Must meet specific population and housing unit thresholds and suggested area and
* Boundaries should follow visible and identifiable features.
Participant Statistical Areas Program (PSAP)
U.S. Census Bureau
From: Reardon, Tim <TReardon(a)mapc.org>
Sent: Monday, March 4, 2019 12:14 PM
To: sdc_mlist(a)lists.berkeley.edu; ctpp-news(a)chrispy.net
Cc: Joshua Wixom (CENSUS/FLD FED); GEO PSAP (CENSUS/GEO); todd.graham(a)metc.state.mn.us
Subject: PSAP -- Other criteria or principles for delineation?
I imagine many of us are busy diving into GUPS and getting started with the delineation
work. Obviously there are specific Census-defined thresholds for each type of statistical
areas, but I’m curious to know if there are other criteria or principles that folks are
using as they consider possible adjustments.
Historical continuity aside, what makes for a good block group or tract? Should we seek to
minimize heterogeneity by drawing boundaries that separate very different
neighborhoods/sub-neighborhoods? Or is it better to have block groups/tracts that include
a more diverse set of households and residents? I would imagine that the approach taken
to these questions will affect not only the confidence intervals of the resulting ACS
tables, but also the results of whatever research uses those tables.
Any opinions or literature references on this topic would be most welcome!
Data Services Director
Metropolitan Area Planning Council, Boston
From: Graham, Todd [mailto:email@example.com]
Sent: Friday, February 22, 2019 1:10 PM
To: sdc_mlist(a)lists.berkeley.edu; ctpp-news(a)chrispy.net
Cc: joshua.wixom(a)census.gov; GEO PSAP (CENSUS/GEO) <geo.psap(a)census.gov>
Subject: [State Data Centers] PSAP participants in every county:
Hi friends of Census Tracts—
If it’s useful to you… Census Bureau has published a contacts list of 2020 Census PSAP
participating agencies, here:
This list covers every county in the nation.
If the listing for your county points to an erroneous agency or a nonworking phone
number/email, I suggest you alert Census’s Geog Division:
By the way, our office, Metropolitan Council of the Twin Cities, has a few upcoming
meetings where we’ll be describing our review, validation and redrawing of Census Tracts
and Block Groups. We are well into the preliminary work. Starting in March we will be
pointing interested stakeholders to preliminary, proposed re-tracting for our 7-county
And we will be inviting stakeholders to comment or express their needs for Census stats
tabulations for sub-city zones, service areas, etc. We will consider whether those needs
can possibly be met with 2020-vintage Tracts and Block Groups.
It’s possible we may receive some comments from outside of our region. When that happens,
we will be redirecting commenters to the other county governments and regional development
commissions in our state… May want to bookmark the participants list mentioned above!
Hope that helps.
Principal Demographer | Metropolitan Council | Research
P. 651.602.1322 | F. 651.602.1674
390 North Robert Street | St. Paul, MN 55101 |
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