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Small Area Income and Poverty Estimates

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Estimation Procedure Changes for the 2011 Estimates

The following items represent changes in the estimation procedures used for school district, county, and state poverty estimates for 2011 relative to the estimation procedures used for 2010. 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 and Guidance for Making Year-to-Year Comparisons.

County Model
There were no changes in the list of county-level entities or methodology in 2011 relative to 2010 estimates.

State Model
There were no changes in the list of state-level entities or methodology in 2011 relative to 2010 estimates.

School District Estimates
The SAIPE school district estimates incorporate the latest available boundary updates produced by the School District Review Program (SDRP), which are updated every two years. Thus for 2011 estimates, boundaries were utilized from the 2011-2012 School District Review Program, completed in 2011 and can be obtained by downloading the SAIPE 2011 school district estimates database, available by state or complete national format. Previous estimates utilized previous versions of the SDRP boundaries.

One change to methodology is the basis for the school district-level population estimates for 2011. These estimates are now based on the decennial 2010 population counts, benchmarked to sum to the Census Bureau’s official county-level population estimates for July 1, 2011.

The other substantial change in the methodology is the replacement of the decennial 2000 sample estimates of school-age poverty as one of the inputs to the school district estimation process with estimates derived from the latest five-year sample of the American Community Survey (ACS 2007-11). In the 2011 decennial census, no long-form survey questions were included. This decennial sample data has now been replaced by the continuous measurement ACS. So the SAIPE program also replaced the decennial sample estimates as an input to the school district process.

There are tradeoffs in using the two different sources as an input to the school district estimation process. The survey associated with the decennial 2000, in general, has lower errors associated with sampling than the ACS five-year survey. To the ACS advantage, the ACS five-year estimates are more timely relative to the decennial 2000 as an input to 2011 estimation. Combining the two effects, preliminary evaluation indicates that the ACS five-year estimate as an estimator of current-year poverty represents an improvement in relative error compared to using the decennial 2000 estimate. The impact on the final SAIPE school-district estimates will thus yield an improvement in precision, but a fuller evaluation is required to give more detail on how the uncertainty of these estimates have improved.


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Source: U.S. Census Bureau | Small Area Income and Poverty Estimates |  Last Revised: December 11, 2013