The inclusion of a geographical isolation factor in a state's distribution formula for foundation aid is a mechanism for providing additional revenue to small schools or school districts that, because of geographical location, cannot be consolidated into more efficient units. This paper presents a model geographical isolation factor that could be adjusted to meet the unique needs of any state with small, isolated schools. The proposed size criterion would extend eligibility for the geographical isolation classification to those elementary and secondary schools having fewer than 150 students in average daily membership. The proposed isolation criterion classifies a school as geographically isolated if it is 10 or more miles from the nearest school of the same level. Revenue entitlements to geographically isolated schools are to be determined on the basis of allowable teacher units, which are dependent on school enrollment and level. A conversion feature allows the entitlement to be computed by weighted pupil units in addition to teacher units. These pages were extracted from a larger work on geographical isolation. (Author/JM)