Key Contact Person: Tina Glover, Associate Research Analyst tglover@sacog.org or (916) 340-6207
Goal of Program: The primary goal of the project is to review and suggest modifications to the 2000 census boundaries for block groups, census tracts, and census designated places (CDP) for purposes of reporting 2010 Census Data. The American Community Survey (ACS), which has replaced the long form, and other Census Bureau programs may also report data for these statistical areas following the 2010 Census.
Time Frame: The late release of materials from the Census Bureau combined with Congressional Deadlines are constraining the amount of time we have to conduct the PSAP. Final suggestions must be submitted by SACOG to the Census Bureau in a designated format by March 30, 2009. In order to make this final date, SACOG will need all suggestions as early as possible, but not later than Thursday March 26 in order to convert the final suggestions into the Census Software that it must be processed through in order to submit by March 30. See timeline below:
Overall Plan: There are two separate portions of PSAP - the Census Designated Place (CDP) portion and the Census Tract/Block Boundary (CTBG) portion. All participants will be asked to submit comments and then review SACOG's consolidated work prior to submissions on each of the two portions. For both programs, only participants that have contacted SACOG prior to March 16, 2009 will be able to suggest changes. Areas that do not respond by this due date will have program comments developed and submitted by SACOG staff.
Comment Suggestions: Comments may include suggestions to change or delete 2000 Census CDPs, Census Tracts and Block Groups, and/or to add new CDPs, Census Tracts and Block Groups. These suggestions may be sent to SACOG in a variety of formats.
E-mail is preferred; this can include text suggestions and/or pdf.'s, GIS .shp files, scanned and emailed maps, etc., to tglover@sacog.org
FAX to: 916-321-9551 attn: Tina Glover
Regular mail is also an option, please keep in mind that due dates are not flexible in this project and if materials are not received by the due dates listed below, suggestions will not be included. SACOG's street address is:
SACOG
Attn: PSAP Tina Glover
1415 L Street, Suite 300
Sacramento, CA 95814
CDP Program
The CDP Program will be of interest primarily to county agencies and other interested parties that need to track changes in the unincorporated area. The program creates and changes the designated place boundaries that allow for more detailed reporting by the Bureau. Cities boundaries are surveyed by the Census Bureau directly through the Census Boundary and Annexation Survey (BAS).
The CDP Program will post PDF Maps to designated liaisons March 10, 2009. Comments will be due March 16. Final reviews of submissions will be emailed out the week of March 23 with comments due on March 26.
CTBG Program
The CTBG Program should be of interest to all agencies. This program takes comments on the Census Tract Boundaries and the Block Group Boundaries used in most of the Census Bureaus reports. Because of the size of the areas we are considering and time we have to conduct this program, SACOG is asking each participant to commit to a paper or Geographic Information Systems process by Friday March 13.
Each participating agency will be given an individual timeline to recommend changes and review comments. All recommendations will be due by March 20 with all final review comments due to SACOG by March 26.
March 4 - 10 - CDP portion version 1 maps distributed
March 11 - 13 - CDP portion version 1 maps comments returned to SACOG
by Monday, March 16 - CTBG portion version 1 maps distributed
by Wednesday, March 18 -- CDP portion combined final suggestions maps distributed
by Monday, March 23 -- Final comments on CDP portion accepted
by Monday, March 23 -- CTBG portion version 1 maps comments returned to SACOG
by Thursday, March 26 -- CTBG portion combined final suggestions maps distributed
Thursday, March 26 -- ALL COMMENTS/SUGGESTIONS MUST BE IN BY THIS DATE IN ORDER TO BE INCLUDED IN THE FINAL DELIVERY TO THE CENSUS BUREAU
Monday, March 30 -- SACOG final due date to deliver PSAP suggestions in the proper format
Email Liaison information and any questions to:
Tina Glover at tglover@sacog.org
PSAP Guidelines for 2010
Sacramento Area Council of Governments (SACOG) 3/4/09
CENSUS DESIGNATED PLACES (CDP)
Definition
Incorporated Places
Cities, towns, boroughs (boundaries are updated annually through the Boundary and Annexation Survey - BAS)
Chartered under the laws of their respective states
Census Designated Places (CDP)
Statistical equivalent of incorporated places, or unincorporated places
Statistical geographic entities representing communities that are:
Closely settled
Unincorporated
Locally recognized
Identified by name
Mix of residential, commercial, retail areas and relatively high residential population density compared to the surrounding area
Boundary comparability over time is desired, but CDPs are organic by definition and can change and go into/out of existence
A record of being historically identified is helpful
Do residents identify themselves with this place?
Do not include subdivisions
Cannot overlap with incorporated places or other CDPs
Cannot exist within a city, town or borough
May reside partially in one or more townships
Evolution of CDPs
Criteria changes:
Capture the diversity and evolution of communities
Meet data user needs
Data tabulation changes
American Community Survey
Economic Census
Potentially data from other censuses and surveys for CDPs
Increase in the usage of CDPs in various federal agency place-based programs
Increase in published studies analyzing CDPs
Criteria changes for 2010
CDPs cannot have zero population and zero housing units
Zero population and housing units is contrary to the concept of 'place'
Must have a minimum of 10 dwelling units
CDPs should have the same name as the Township in which they reside
Hyphenated CDP names are to be avoided
Only acceptable where 2 or more communities are perceived to be a single area
2010 PSAP Suggested Updates for CDPs
Edit CDPs that have fewer than 10 housing units
Create a new CDP
Remove a CDP
Edit CDP boundaries to depict the community boundaries
Update the name to represent the name of the community
Identify any and all small rural communities by name and boundaries for inclusion
CENSUS TRACTS
Definition
Small, relatively permanent statistical subdivisions of a county or a statistically equivalent entity
Relatively consistent boundaries over time
Ideally, tract boundaries remain stable between censuses, making it possible to compare statistics from census to census.
Suggestions to change 2000 Census Tract boundaries may be made, but the Census Bureau encourages participants to keep them at a minimum and instead focus on splitting or merging 2000 Census Tract boundaries rather than creating completely new boundaries for all Census Tracts.
Census tracts will be used to present American Community Survey (ACS) data in addition to decennial census data
The ACS has replaced the census long form
The ACS is designed to produce local area data as of a 12 month period average
To accommodate this change, participants may use either population counts or housing units in the Census Tract review.
Census Tracts Thresholds
Census 2000
2010 Census
Population
Population
Housing Units
Optimum
4,000
4,000
1,600
Minimum
1,500
1,200
480
Maximum
8,000
8,000
3,200
Population counts or housing units counts must meet thresholds
All types of populated tracts meet the same thresholds
National standard
Reliability of sample data
Change minimum population threshold to 1,200
Reliability of sample data
Avoid application of disclosure avoidance methodologies
Meet thresholds by splitting and merging
Statistical Area Boundary Criteria
Acceptable Features:
Legal and administrative boundaries
Visible features - perennial hydrography, roads, railroads, utility transmission lines, cliffs, etc.
Questionable Features:
Nonstandard boundary features - intermittent hydrography, property/parcel lines, hiking/biking trails, driveways, etc.
Feature extensions & lines of sight - short, point-to-point, 180 degree, clear lines of sight are acceptable
Unacceptable Features:
Superseded legal and administrative boundaries
Paper streets
Lines of sight that intersect buildings, property lines, rights-of-way, or other lines of sight
2010 PSAP Suggested Updates for Census Tracts
Split above maximum tracts (3,200 housing units)
Merge below minimum tracts (480 housing units)
Delineate special land use tracts, if desired
Edit census tract boundaries to follow eligible boundary features
Maintain 2000 Census Tract boundaries wherever possible
BLOCK GROUPS
Definition
Block groups nest within census tracts
Smallest area for ACS sample data tabulation
Continuity and comparability from one census to another much less of a concern
Block Group Thresholds
Census 2000
2010 Census
Population
Population
Housing Units
Optimum
1,500
---
---
Minimum
600
600
240
Maximum
3,000
3,000
1,200
Population counts or housing unit counts to meet thresholds
All types of populated block groups meet the same thresholds
2010 PSAP Suggested Updates
Split above maximum block groups (1,200 housing units)
Merge below minimum block groups (240 housing units)
Edit block group boundaries to follow eligible boundary features
For Additional Information or Questions please contact:
Tina Glover, Associate Research Analyst, SACOG
Email: (preferred) tglover@sacog.org
Direct: (916) 340-6207
Main: (916) 321-9000
FAX: (916) 321-9551
County Level Maps
CDP Version 1 maps and SACOG suggested changes for 2010 CDPs
