This document presents a model for student organization development, defining in detail the central conditions for the CORE model (Cohesion, Organization, Resourcefulness, and Energy); and provides an assessment tool, the CORE Conditions Checklist, for checking the extent to which these conditions are present in organizations. The CORE model is comprised of three concentric rings, the central ring containing the four CORE conditions which activate an organization to meet its needs. These student organization needs (i.e., fund raising, recruitment, leadership, group unity) are contained in the second ring. The third ring contains ten student development domains (e.g., forming friendships, developing interpersonal and task competencies) which are the long range goals of student organization development. The CORE conditions make these long range goals possible. Factors which comprise these conditions are: (1) involvement and participation, group affiliation and commitment, a shared sense of mission, belongingness, and helpfulness and friendship (Cohesion); (2) purposes, structure, policies and procedures, rewards, and leadership (Organization); (3) student organization knowledge, campus knowledge, and personal, interpersonal, and task competencies (Resourcefulness); and (4) positive motivation, innovation, responsibility, cooperation, and adaptability (Energy). The 100-item CORE Conditions Checklist, which is appended, is a tool for student organizations, or those working with them, to assess member perceptions of the organization. (WAS)