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Census.govPopulation SAIPE Main SAIPE MethodologyEstimation Details for School Districts Data › 2010-2011 Overview of School District Estimates

2010-2011 Overview of School District Estimates

This page describes statistical and geographic inputs to the Small Area Income and Poverty programs estimation of school district-level poverty for children ages 5 to 17 in families. For more technical details on the numeric process, see Constructing the SAIPE Program Estimates further on this page. Two changes to the methodology were implemented for the 2010 estimates, described in detail in Estimation Procedure Changes. In brief, the two changes were integrating population estimates based on the decennial 2010 population counts and replacing the decennial 2000 sample estimates of poverty with estimates from the five-year American Community Survey (ACS) sample, 2006-2010.

The No Child Left Behind Act of 2001 (NCLB) directs the Department of Education to distribute Title I basic and concentration grants directly to school districts on the basis of the most recent estimates of children in poverty available from the Census Bureau. These estimates are produced under the Census Bureau's Small Area Income and Poverty Estimates (SAIPE) program. They are based on multiyear American Community Survey (ACS 2006-10) estimates, aggregated tax data, and the SAIPE program's model-based estimates of poverty for all counties.

SAIPE school district estimates incorporate updated school district boundaries every two years. Thus, the 2010 estimates correspond with 2009-2010 school district boundaries. There were small revisions to these boundaries associated with the final decennial 2010 tabulation, which were incorporated into the 2010 estimates. No new districts were added in this revision, and no districts deleted. Changes in the population of school-age children within school district boundaries caused by this revision did not exceed one-half of one percent for any district nationwide.

SAIPE School District Estimates
Three estimates are provided for each school district:

  • total population
  • children ages 5-17
  • related children ages 5-17 in families in poverty

The number of related school-age children in families in poverty in each school district is provided as a component of the determination of Title I grants. The estimate of the total population of each district is provided for use in the small district (fewer than 20,000 population) provision. The figure for school-age children is provided so that the proportion of children in poverty can be determined. This proportion is required for determining eligibility for grants. A true poverty "rate" for children cannot be determined from these figures, because the numerator and denominator refer to slightly different universes.

The 2010 school district estimates are based upon tabulations of poverty from the five year ACS sample, 2006-2010, and tax year 2009 IRS income tax data, using school district boundaries corresponding to school year 2009-2010, as revised for the final decennial 2010 tabulation. These sub-county inputs are then combined with the SAIPE program 2010 county estimates of poverty. By construction, the SAIPE program school district estimates are arithmetically consistent with the SAIPE program county and state estimates.

Spatial Boundaries of School Districts
We provide poverty estimates for all school districts that are in the Census Bureau's TIGER database, updated by each School District Review Program; the most recent was completed in 2010. We also tabulate and produce estimates for all occupied areas not assigned to any school district. We refer to these areas as "balances" of the counties in which they occur, whether they compose a single compact area or not. Although we do not publish estimates for "balance of county" areas on our website, they are provided to the U.S. Department of Education for implementing provisions of NCLB and are available upon request.

Grade Ranges of School Districts
For each school district, our estimates pertain to all resident school-age children ages 5-17, inclusive, whether enrolled in public or private school, or not enrolled. Where two districts divide the children of an area between them by grade, the estimates do so as well. In most areas, districts called "elementary" or "unified" are, no matter their names, responsible for providing education for all elementary and secondary grades - either by operating schools themselves or by purchasing instruction from neighboring school districts - for all residents of their territory. In these areas, data for all people ages 5-17, inclusive, are tabulated in the district in which they reside.

Some states have areas with separate "elementary" and "secondary" school districts, each exclusively responsible for providing education in some grades in their shared territory.1 In these areas, data for school-age children are allocated between districts on the basis of the grade range of the district and the grade assigned to the child. There are also some states that have school districts with different grade ranges in different parts of their territory.2 In most cases, these are districts that are "unified" in part of their domain and "secondary" in the rest. The final tabulations and estimates reflect the combination of data honoring these distinctions.

Grade ranges for each district are collected during the boundary update and supplemented with phone calls to districts. We attempt to assign a single grade range to each district that, in the case of spatially overlapping districts, leaves no grade unclaimed and no grade claimed by more than one district. Occasionally the pattern of grade ranges of overlapping districts does not permit each grade to be assigned to exactly one and only one district. In these few instances, three simple rules are applied.

  • If a "unified" district is present, data for children whose assigned grade is claimed by two districts or not claimed by either are allocated to the "unified" district.
  • If an "elementary" and "secondary" district are present, data for children whose assigned grade is claimed by both are allocated to the "secondary" district.
  • If an "elementary" and "secondary" district are present, data for children whose assigned grade is claimed by neither are allocated to the "elementary" district.

Grades for Children
To tabulate the data for each district, each child is assigned a grade. In both the ACS sample and the decennial 2010 tabulation used for population estimates, the grade of each child is assigned on a one-to-one basis relative to the child’s age. Under this process, a child of age five is assigned to kindergarten, age 6 to first grade, and so on.
With the Census 2010 record, and ACS 2006-2010 sample response, for each child assigned to a single school district, to which that child is said to be "relevant," we tabulate for each district:

  • "relevant" children ages 5-17, inclusive,
  • "relevant" children who are related to the householder and reside in families whose income falls below the poverty threshold appropriate to that family, and
  • the total population of all ages residing in the spatial boundaries of the district. (Note that because of overlapping districts, the sum of the total populations of the districts will exceed the total population of the nation.)

Related children are people ages 5-17 related by birth, marriage, or adoption to the householder of the housing unit in which they reside; foster children, other unrelated individuals, and residents of group quarters are not "related children."

Constructing the SAIPE Program Estimates
The SAIPE program procedure for estimating poverty among relevant children ages 5-17 in families works with geographical units we call school district-county-pieces. These pieces are defined as the intersections of school districts and counties (i.e., all of a district if it does not cross county boundaries and each county part separately for districts that do). If a school district has territory in two counties, for example, we make estimates for the two parts separately and then combine them.

The first part in making school district poverty estimates is to compute the school district piece tax-based child poverty rate, using federal tax information obtained from the IRS. The tax-based poverty rate for a school district piece is estimated by the product of the county related children ages 5-17 poverty rate and the ratio of school district piece to county share of "child tax-poor exemptions" over the share of total "child tax exemptions". For the 2010 school district estimates, the number of child tax exemptions and their corresponding poverty status are taken from tax year 2009 IRS income tax data. "Poor Child Exemptions" are defined as the number of child tax exemptions on returns whose adjusted gross income falls below the official poverty threshold for a family of the size implied by the number of exemptions on the form tabulated for each school district piece.

Not all tax returns can be geocoded down to a specific school district piece. However, the total number of exemptions in a county is known. These exemptions will be called the non-geocoded exemptions. The tabulated child tax exemptions and child tax-poor exemption counts are adjusted to reflect the appropriate grade range of the school district piece because age of child is not included on the income tax form. The next step in calculating the tax-based shares is to estimate the school district piece to county share of relevant children age 5-17 and relevant children age 5-17 in poverty from ACS five-year sample, 2006-2010. The non-geocoded exemptions are also adjusted to reflect the target 5-17 year old population, then allocated to the school district pieces to minimize the difference between the tax-based shares and the corresponding census-based shares using the Minimum Change algorithm (for details see report: Small Area Estimation of School District Child Population and Poverty: Studying the Use of IRS Income Tax Data [PDF 373k]). After allocating the non-geocoded exemptions, the tax-based poverty rate for a school district piece can be computed.

The second part in creating the school district poverty estimates is to multiply the school district piece poverty rate to the official estimate of relevant child population for the school district piece. These estimates are then raked (ratio adjusted) to agree with the county estimates for number of children age 5-17 in poverty. Finally, the raked school district piece estimates are adjusted using "controlled rounding" to get results with the following properties.

  • The number of children in poverty in the pieces in a county adds up to the SAIPE program's model-based estimate of the number of children in poverty in their counties for the relevant income year.
  • The number of children in poverty in the school district pieces are integers.

The final step is to reassemble the school district pieces into the school districts, simply by adding their controlled-rounded numbers of children in poverty together.

1 States where districts may overlap: Arizona, California, Connecticut, Georgia, Illinois, Kentucky, Maine, Massachusetts, Montana, New Hampshire, New Jersey, New York, Oregon, Rhode Island, South Carolina, Tennessee, Texas, Vermont, and Wisconsin.

2 States where grade ranges may differ within a district: California, Georgia, Illinois, Kentucky, Massachusetts, South Carolina, Tennessee, and Texas.

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