Abstract
The study was aimed at developing an instrument for measuring trainees' competencies in leading counseling and psychotherapy groups. Foundation of the original 60 items of Group Leadership Competence Scale (GLCS) were proposed mainly based on group theory, researchers' previous research findings, group counselor training practices, and literature reviews. After evaluated by six professionals for content validity, three items CVI lower than .70 were deleted and two similar items were integrated into one, then the version of remaining 56 items were used. 258 valid samples were gathered for analyzing the critical ratio and test their internal consistency. 7 items were deleted and only 49 items were left for examining the validity and reliability. The reliability of internal consistency correlation α =.97 0, and split-half correlation γ (subscript xx) = .935. The validity of GLCS showed a 8-factors structure by factor analysis, and that were competence of Change and Action Facilitating, Cohesion Facilitating, Group Depth Enhancing, Process Leading & Facilitating, Individual Depth Enhancing, Norm Building, Process Obstacle Breaking through, and Terminating & Change Intensifying. Furthermore, Pearson's correlation with the ”Professional Ability Scale for Group Counseling Leader” γ = .697. Based on those well acceptable evidences for the validity and reliability of the instrument, its advanced application in practice and research were discussed and recommended.