[CTPP] PUMA Update

[Ed Christopher]

Someone passed me this today.  Apparently it was posted to the State 
Data Center list serve and provides the current status of what is known 
about PUMAs.  PUMAs are of special importance to the transportation 
community since they are now a tabulation geography for ACS and provide 
the only wall-to-wall coverage of annual ACS data for metropolitan 
areas.  If anyone along this list will be involved with the referenced 
October 14-16 State Data Center meeting please let us know what minimum 
population thresholds the CB plans to propose for tract based PUMAs.

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State Data Center Network:

The Census Bureau is currently drafting the 2010 Public Use Microdata 
Area (PUMA) delineation proposed criteria.  These draft proposed 
criteria were developed based on internal meetings with key Census 
Bureau stakeholders, and with consideration of new challenges and issues 
associated with the use of PUMAs in the publication of annual American 
Community Survey (ACS) Public Use Microdata Sample (PUMS) data as well 
as in the publication of ACS estimates.

The Census Bureau will present the 2010 PUMA delineation proposed 
criteria at the upcoming State Data Center Annual Meeting (October 
14-16, 2009) for discussion and comment.  Subsequently, pending the 
approval of the Census Bureau’s Statistical Areas Committee, the Census 
Bureau will publish the 2010 PUMAs proposed criteria in the Federal 
Register for public comment. State Data Centers (SDCs) will use the 
final version of these criteria, as published in a forthcoming Federal 
Register, to delineate PUMAs for Census 2010 and the ACS.

For your consideration, the following represents a high level summary of 
the planned 2010 PUMA delineation proposed criteria:

1. PUMA types: One “level” of PUMAs will be delineated for the United 
States, Puerto Rico, Guam, and the U.S. Virgin Islands, as compared with 
two “levels” of PUMAs for Census 2000 (super-PUMAs and standard PUMAs). 
  Additionally, place of work PUMAs (POW PUMAs) and migration PUMAs (MIG 
PUMAs) will be based on a single PUMA for county-based PUMAs or an 
aggregation of adjacent PUMAs for tract-based PUMAs.  Note: All 
subsequent references to PUMAs in this document, unless preceded by 
“POW” or “MIG”, refer to these standard PUMAs.

2. Population Thresholds: Each PUMA must contain a minimum population of 
100,000 both at the time of delineation and throughout the decade for 
the publication of ACS PUMS data and ACS estimates.  For those areas 
currently experiencing population decline, or where population decline 
throughout the decade is expected, PUMAs should be initially delineated 
to include a population significantly higher than 100,000 persons to 
accommodate this change.  Should the population of a PUMA fall 
significantly below the 100,000 person threshold, the PUMA will be 
combined with one or more adjacent PUMAs for ACS PUMS and ACS estimate 
publication.

3. PUMA Composition: All PUMA types (PUMAs, POW PUMAs and MIG PUMAs) 
must nest within states (i.e., may not cross state boundaries).   PUMAs 
will be based on aggregations of counties and census tracts only. 
Incorporated places and MCDs will not be used as building blocks for 
2010 PUMAs. Census tracts may be aggregated to approximate minor civil 
divisions, incorporated places, or census designated places.

Provided the PUMA meets the minimum population threshold:
a.  One county may be designated as a PUMA
b.  Two or more contiguous counties may be aggregated to create a PUMA
c.  Contiguous census tracts may be aggregated to create a PUMA
	Tract-based PUMAs may cross county boundaries, provided that each 
PUMA-county part meets a minimum area and/or population threshold (TBD - 
The Census Bureau is currently determining an appropriate minimum area 
and population threshold for these areas, and will provide these minimum 
thresholds at the SDC Annual Meeting in October).
	Census tract aggregations may compose or approximate the extent of 
other types of geographic entities, including minor civil divisions, 
incorporated places, and census designated places.

4. PUMA contiguity In all cases, each PUMA must constitute a 
geographically contiguous area. Limited exceptions are presented here:
a. A PUMA may be discontiguous if a county is discontiguous.
b. A PUMA may be discontiguous when it surrounds another whole PUMA, 
e.g., if census tracts define a PUMA that approximates an incorporated 
place or census designated place, a PUMA may be defined to encompass the 
area within the county surrounding the place

The Census Bureau also intends to propose additional guidelines to which 
delineation participants are strongly encouraged, but not required to, 
adhere.

For your consideration, the following represents a high level summary of 
the planned 2010 PUMA guidelines:

1. Wherever possible, each PUMA should comprise an area that is either 
entirely inside or entirely outside Core Based Statistical Areas
2. The Census Bureau recommends that the number of five-percent PUMAs be 
maximized, and that five-percent PUMAs should not contain more than 
200,000 people, wherever possible, unless the PUMA is defined for an 
area that is or will be experiencing population decline.

We appreciate your interest in the 2010 PUMA delineation program, and 
look forward to discussing the planned proposed criteria with you at the 
SDC Annual Meeting in October 2009.  Should you have more immediate 
questions please contact the Geographic Standards and Criteria Branch 
PUMA team at geo.puma at census.gov.
-- 
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)

FHWA RC-TST-PLN
4749 Lincoln Mall Drive, Suite 600
Matteson, IL  60443