Before NCLB
In 1999, a Class Size Reduction (CSR) program was added to the Elementary and Secondary Education Act of 1965 (ESEA). The goal of the CSR program was to improve educational achievement by reducing class size with fully qualified teachers. Special attention was focused on class size reduction in the early elementary grades to 18 or fewer students. To accomplish the class size reduction goal, the program sought to fund the hiring of 100,000 fully qualified teachers for grades kindergarten through third grade within seven years. The appropriations were $1.2 billion in 1999, $1.3 billion in 2000, and $1.623 billion in 2001. The CSR program was only in effect from 1999 to 2001. In its first two years, 37,000 teachers were hired.
This video offers a teacher's point of view on class size.