Embracing Scientific Humility and Complexity: Learning "What Works for Whom" in Youth Psychotherapy Research.

Clinical psychological scientists have spent decades attempting to understand "what works for whom" in the context of youth psychotherapy, toward the longstanding goal of personalizing psychosocial interventions to fit individual needs and characteristics. However, as the articles in this Special Issue jointly underscore, more than 50 years of psychotherapy research has yet to help us realize this goal. In this introduction to the special issue, we outline how and why "aspiration-method mismatches" have hampered progress toward identifying moderators of youth psychotherapy; emphasize the need to embrace etiological complexity and scientific humility in pursuing new methodological solutions and propose individual and structural strategies for better-aligning clinical research methods with the goal of personalizing mental health care for youth with diverse identities and treatment needs.