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Estimation Procedure Changes for the 2006 - 2008 Estimates

The following items represent changes in the estimation procedures used for school district, county, and state and poverty estimates for 2006, 2007 and 2008 relative to the estimation procedures used for 2005. These changes reduce the comparability of the estimates between years and should be considered when making such comparisons. See General Cautions about Comparisons of Estimates.

ACS Group Quarters

The 2006, 2007 and 2008 American Community Survey (ACS) estimates, which are used for the latest SAIPE state and county modeling, had one change relative to the 2005 ACS estimates used for 2005 SAIPE modeling.

In 2005 and prior years, poverty status in the ACS was determined only for individuals living in households.  Residents of group quarters, such as nursing homes, dormitories, shelters and other joint living quarters were not surveyed.  In the 2006, 2007 and 2008 ACS, some group quarter residents are included in the poverty universe, which is the term used for individuals for whom poverty status is determined.  The group quarters residents included in the poverty universe are non-institutional group quarters residents, apart from college dormitories and military housing.  These quarters include shelters, halfway houses, emergency housing facilities, and other structures not classified elsewhere.

Residents of these non-institutional group quarters in general have higher poverty rates than residents of households.  Thus, when comparing estimates from 2006, 2007 and 2008 to those from earlier years, this specific caution should be considered.  For more information, see the Detailed Information on 2006 ACS Data Comparisons.

Special Processing for Areas Affected by Hurricanes Katrina and Rita

The Federal Emergency Management Agency (FEMA) declared 117 counties to be disaster areas in Alabama, Louisiana, Mississippi, and Texas as a result of hurricanes Katrina and Rita in August and September 2005, respectively.  The Population Estimates Program (PEP) of the U.S. Census Bureau used supplemental data, such as the U.S. Postal Services' National Change of Address Form, to track the movements of people displaced by Hurricanes Katrina and Rita.  More details can be obtained from the Population Estimates Program methodology.

The SAIPE program used these PEP population estimates for the Hurricane-affected areas in the production of its 2006, 2007 and 2008 income and poverty estimates.  Where the relation of other inputs in the SAIPE models to population estimates diverged from historical norms for the 2006, 2007 and 2008 models, we adjusted these inputs back near their historical relationships.  Adjustments of this nature were required at the county level for decennial census poverty, transfer income, personal income growth and Supplemental Nutrition Assistance Program (SNAP) benefits in 2006, and for decennial census poverty, personal income growth, and tax exemptions in 2007, and for decennial census poverty in 2008.

Note as of Oct. 1, 2008, the federal Food Stamp Program is now named Supplemental Nutrition Assistance Program (SNAP).

Further information about Hurricanes Katrina and Rita is available at:

Hurricane Rita

Hurricane Katrina

State Model

There were no changes to the methods used to estimate state SAIPE poverty levels for 2006, 2007 or 2008 compared to the 2005 methods.  Regarding the input data used, a special adjustment was made for SNAP benefits in the state of Vermont to account for a known small historical error by Vermont Agency for Human Services in extracting Vermont SNAP cases.  Additionally, the demographic estimates of the poverty universe used to transform poverty levels into reported rates now include residents of non-institutional group quarters, not elsewhere classified.  This is consistent with the ACS group quarters change cited above.

County Model

There were no changes to the methods used to estimate county SAIPE poverty levels for 2006, 2007 or 2008 compared to the 2005 methods.  Regarding the input data used, the demographic estimates of the poverty universe used to transform poverty levels into reported rates now include residents of non-institutional group quarters, not elsewhere classified.  This is consistent with the ACS group quarters change cited above.

School District Level

The 2007 and 2008 SAIPE school district estimates incorporate the latest available boundary updates produced by the 2007-2008 School District Review Program. (The 2009-2010 School District Review Program to produce boundaries for SAIPE 2009 is already underway.) This update means that the list of school districts has also been updated, with new districts being added to estimation and dissolved districts being removed.  The new list of school districts can be obtained by downloading the SAIPE 2007 school district estimates database, available by state or complete national format.  Finally, regarding the methodology for school districts, there were no production changes for 2006, 2007 and 2008 relative to 2005.


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Source: U.S. Census Bureau | Small Area Income and Poverty Estimates |  Last Revised: April 29, 2013