Pennsylvania Department of Education. Once you've narrowed your selection, under Percentage Enrolled by Student Group, you'll see economically disadvantaged.
For statistical purposes (e.g., counting the poor population), the United States Census Bureau uses a set of annual income levels. Links to yearly poverty thresholds back to 1959. U.S Census Bureau.
The Small Area Income and Poverty Estimates (SAIPE) program provides more current estimates of selected income and poverty statistics than those from the most recent decennial census. Estimates are produced for school districts, counties, and states. U.S. Census Bureau.
2021. The Supplemental Poverty Measure is designed as an experimental poverty measure that defines income thresholds and resources in a manner different from the official poverty measure. U.S. Census Bureau.
Annual report on persons who, during the year, spent 27 weeks or more in the labor force (working or looking for work), but whose incomes still fell below the official poverty level. U. S. Department of Labor, Bureau of Labor Statistics.