Validating a Special Olympics Volleyball Skills Assessment Test

Abstract

This study examined the validity and reliability of a Volleyball Skills Assessment Test (VSAT) as a measure of volleyball skill and as a predictor of team success in Special Olympics International (SOI) volleyball competition. Test-retest reliability data from 130 SOI volleyball players with mental retardation (101 males and 29 females) in the sixth week of an SOI volleyball training program yielded intraclass reliability coefficients (R) above .80 for all VSAT subtests (forearm pass, spike, set, serve) across gender with the exception of the set test for females (R = .75). Multivariate test battery test–retest reliability, examined using canonical correlation analysis, yielded moderate total redundancy estimates ranging between 62.5 and 66.1%. A high degree of concurrent validity was evidenced when correlating VSAT scores with judges’ ratings of performance on the four skills: r = .93 (r2 = .86) serve, r = .94 (r2 = .88) pass, r = .98 (r2 = .96) spike, and r = .86 (r2 = .74) set. Contingency table analysis, multiple regression, and discriminant function analysis revealed that the predictive validity of the VSAT as the primary determinant for allocating teams to pools of equal ability is questionable.