Conceptualization and Formulation are terms often used interchangeably, but the authors prefer to differentiate between them in an attempt to better clarify their defining characteristics: conceptualization is the process of understanding and interpreting the patient's problems through the integration of assessment data, while formulation is a subsequent and more focused phase that applies a theoretical model to describe the problems, their causes, and maintaining factors in order to effectively guide therapy. In other words, case formulation is the result of the conceptualization process in which the clinician considers the life experiences that lead the patient to think and behave in a certain way, and combines this information into a coherent story.

In summary, conceptualization provides basic understanding, while formulation uses this understanding to create a specific model that guides therapeutic intervention.