In 2005, AAIDD published the first edition of Clinical Judgment to assist clinicians in making decisions or recommendations that were of high quality, valid, and precise. This need was becoming increasingly important as the field of intellectual disability was moving to a community-based service delivery system in which the concepts of equity, inclusion, self-determination, and empowerment were merging with the supports paradigm and the self-advocacy movement. Thus, clinicians were being asked to formulate high-stakes decisions and recommendations that frequently required a level of competency that extended beyond their formal training. In this second edition, the authors maintain their focus on the use of clinical judgment in situations involving diagnosis, classification, and planning supports. In addition they have synthesized evaluative input from colleagues and literature-based critiques and have extended their analysis and evaluation of the role of clinical judgment in decision making.