Technical Note: Measuring the Concentration of Student Poverty in Schools
The National School Lunch Program (NSLP), in the U.S. Department of Agriculture, oversees the national free or reduced-price lunch (FRPL) program. Children from families with incomes at or below 130 percent of the poverty level are eligible for free meals. Those from families with incomes that are above 130 and up to 185 percent of the poverty level are eligible for reduced-price meals (Ralston et al. 2008). For 2009–10, the income of a family of four at 130 percent of the poverty level was $28,665, and the income of a family of four at 185 percent of the poverty level was $40,793.
FRPL is commonly used to measure school poverty because (1) it is found consistently across survey collections (unlike other measures such as household income); (2) at the district level, it has a strong correlation with district poverty; and (3) at the student level it is correlated with measures of socioeconomic status (SES) reported at the student/household level.
For this report, the basis for the measurement of the concentration of student poverty in a school is the percentage of a school's enrollment that is either eligible for or actually enrolled in the FRPL program, depending on the data source used. Data from the Common Core of Data (CCD), a comprehensive, annual, national collection of data on all public elementary and secondary schools and school districts, are based on district-level submissions of the number of students who are eligible for the program. The Schools and Staffing Survey (SASS), a sample survey of American schools that provides data on school staffing and other conditions in schools, asks principals, "Around the first of October, how many students at this school were approved for free or reduced-price lunches?" Data from the School Survey on Crime and Safety (SSOCS), a national, cross-sectional survey of public elementary and secondary schools that collects information on crime and safety, asked principals to report "the percentage of their current students that are eligible for free or reduced-price lunch." Data from the National Assessment of Educational Progress (NAEP) are based on a survey given to principals in the participating schools. The survey asks principals "about what percentage of students in your school was eligible to receive a free or reduced-price lunch through the National School Lunch Program?" with nine categories to select from: 0 percent, 1–5 percent, 6–10 percent, 11–25 percent, 26–34 percent, 35–50 percent, 51–75 percent, 76–99 percent, and 100 percent. For consistency, the term eligible is used throughout this section to describe the students who are reported.
As enrollment is voluntary (Entwisle and Astone 1994; Ralston et al. 2008), enrollment may be lower for eligible older students who have greater feelings of stigma associated with FRPL, greater feelings of independence, and more complaints about food quality and choices (Glantz et al. 1994). Due to the inherent difficulty in identifying students who may be eligible for FRPL, but are not enrolled, it is likely that, regardless of the source, the data reflect enrolled students.
The FRPL measure for school concentration of students from low-income families is constructed using absolute thresholds at 0–25 percent, 26–50 percent, 51–75 percent, and 76–100 percent. Separate findings are reported for elementary schools and for secondary schools given the systematic differences in FRPL rates and school level. A small percentage of schools either did not report the number of students eligible for FRPL or do not participate in the program. For CCD, SASS, and SSOCS data, schools in this category are counted in the totals, but not always shown separately in tables in the full report. For NAEP, which may have schools that do not participate in the program, but does not have missing school level data due to extensive data collection efforts for those schools in the NAEP sample, schools in this category are included in the low-poverty category (0–25 percent).