Research for the AASHTO Standing Committee on Planning. Task 135. Addressing Margins of Error in Small Areas of Data Delivered through the American Fact Finder or the Census Transportation Planning Products Program

As the Census Bureau has moved to the American Community Survey the sample size surveyed has shrunk dramatically when compared to the now discontinued Long Form.  After five years of data collection, small area data are delivered either through American Fact Finder or the Census Transportation Planning Products Program (CTPP).  When working with small, but sometime larger areas, margins of error (MOE) that are a large proportion of the estimate, and that may in some cases exceed the estimate itself, may be encountered.  The American Community Survey (ACS) data is now the only source of large national data on Journey to Work and the huge amount of commensurate demographic data that accompanies it.  The ACS and CTPP are routinely used by planners at all levels of government to develop long range plans, validate and calibrate traffic models, and provide information to decision makers to deploy transportation dollars.  Inappropriate handling of the inherent vagaries of the data can negatively impact the quality of information used for decision-making.  Guidance on how best to address these issues is needed. The objective of this research is to provide guidance on how to appropriately handle large MOEs that is tailored to the application of the data, e.g. long range planning or calibrating a travel demand model.  The guidance should also address how to communicate MOE when data are represented visually, e.g. in heat maps or pie charts, and when the use of ACS data is spread too thinly to constitute an appropriate use of the data.


  • English


  • Status: Completed
  • Funding: $74997
  • Contract Numbers:

    Project 08-36, Task 135

  • Sponsor Organizations:

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Goldstein, Lawrence

  • Performing Organizations:

    Rand Corporation

    1700 Main Street, P.O. Box 2138
    Santa Monica, CA  United States  90401-2138
  • Principal Investigators:

    Krenzke, Tom

  • Start Date: 20150925
  • Expected Completion Date: 20170501
  • Actual Completion Date: 0
  • Source Data: RiP Project 40791

Subject/Index Terms

Filing Info

  • Accession Number: 01598815
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 08-36, Task 135
  • Files: TRB, RiP
  • Created Date: May 4 2016 1:00AM