Title I, Part A (Title I) of the Elementary and Secondary Education Act, as amended by the Every Student Succeeds Act (ESEA) provides supplemental financial assistance to school districts for children from low-income families. Its purpose is to provide all children significant opportunity to receive a fair, equitable, and high-quality education, and to close educational achievement gaps by allocating federal funds for education programs and services. Title I allocations to state education agencies and local education agencies (LEAs) are based primarily on annually updated LEA poverty estimates produced by the U.S. Census Bureau. Then, within-LEA allocations to schools are based on school poverty rates, for which a common measure used by LEAs is the number of public school children eligible for free or reduced-price lunch (FRPL). However, not all Title I-eligible schools participate in Title I programs, due to rules governing within-LEA allocations and state and district flexibility for allocating Title I funds. These rules also mean that Title I per-pupil allocations for schools vary across schools within LEAs, across LEAs within a state, and across states.