The Korean Scales for Predicting Successful Inclusion: KSPSI is a rating scales of four subtests that measure different but interrelated potentials for success in general education classes of children with disabilities. The KSPSI is an individually administered measure of potentials for success in general education classes, standardized on a large, representative nationwide sample of normal and exceptional children ages 6 through 11 years. The normative sample consists of 772 children residing in Kore. For tests such as the KSPSI, reliability coefficients must approximate or exceed .80 in magnitude for the test to be considered minimally reliable. Three types of errors that can affect the reliability of the KSPSI were examined: (a)internal consistency coefficient, (b)measurement error, (c)stability reliability, and (d)inter-rater reliability. All the mean alpha for the subtests are acceptable in that they are range from .84 to .98. Mean alpha for the composites are all in the .90s. The test-retest reliability coefficients for the four subtests are range from .82 to .98. Mean test-retest coefficients are all in the .90s. The scorer reliability for the four subtests are range from .84 to .94, which are great enough to be accepted as evidence of the KSPSI\'s inter-rater reliability. Three interrelated types of validity were examined for the KSPSI: content, criterion-related, and construct. One demonstrations of content validity was offered. The procedures for validity of the item analysis were used during the developmental stages of the test\'s construction to choose items. Interrelated potential abilities for success in general education classes of children with disabilities are an important area in inclusive education. The absence of technically adequate tests of interrelated potential abilities for success in general education classes of children with disabilities were problems to both clinicians and researchers. Professionals need well-constructed tests of interrelated potential abilities for success in general education classes of children with disabilities that can be used with confidence to identify disabled children for inclusive education, to test the effectiveness of any treatment program, or to serve as variables in research attempting to study interrelated potential abilities. key words : Inclusion, Psychometric properties