Exhibit 2 reads: The additional expenditure to provide regular and special education services to students with disabilities is estimated to be $5,918 (=$12,639 - $165 - $6,556). This concept of additional expenditure is the same as the concept of excess cost used in a previous study (Moore et al., 1988) of special education expenditures. For a more complete discussion of the use and meaning of these terms, see the section on the conceptual framework presented in the current report.