When IDEA was enacted, it was estimated that children with disabilities cost approximately twice as much to educate as other children. Congress took that estimate figure into account when setting the maximum federal contribution at 40 percent of state average per pupil expenditure. Estimates of excess cost have not changed much over time. A recent study, using data from the 1999-2000 school year, found that schools spent 1.9 times more in total expenditures and 2.08 times more in current operating expenditures on student with disabilities. Rising special education spending is primarily the result of an expansion of the student population identified as "disabled," and less the result of a disproportionate increase in the cost of special education services.
As described above, IDEA Part B funds two separate sections, 611 and 619. Section 619 is available specifically for children age 3 through 5. As with other sections of IDEA, Section 619 is not “fully funded.” Indeed, Section 619 is funded at a lower per-pupil rate than Section 611. For instance, in fiscal year 2014, the average per-pupil expenditure is $1,743 for PreK-12 special education students (Sec. 611) and only $471 for 3- to 5-year-olds receiving special education services (Sec. 619). Section 619 dollars should be viewed as supplemental funding to the Section 611 funds.
Many, if not most, school districts use a combination of Sections 611 and 619 funding to cover the costs of special education for young children with disabilities. For example, a special education teacher may work full time at an elementary school that also provides pre-K education on site; that teacher may be entirely funded through Section 611 dollars, but still work with a 4-year-old with disabilities.