Psychologists are licensed health professionals, regulated by provincial statute and governed by the College of Psychologists of Ontario. Psychologists practice within the framework of the Regulated Health Professions Act (RHPA).

Assessments can be conducted to address specific questions, and to help guide treatment planning or decision-making; identifying and understanding different presentations and problems, diagnosing when needed or helpful, and then formulating a treatment plan is an important sequence of events in providing sound, effective clinical services.