ABSTRACT Financial planning has matured in theory and professional standards yet remains underdeveloped in intervention science—the rigorous testing of what financial planners do and its impact on client behavior . The purpose of this article is to describe and advocate for single‐case research (SCR) methods as a framework for building a cumulative evidence base in financial planning and wealth management. We argue that SCR methods, well established in counseling, education, exercise science, and rehabilitation, offer a practical, ethical, and scientifically credible approach to closing the research‐to‐practice gap. SCR tests cause‐and‐effect relationships within individual clients, can be replicated across cases and settings, and readily integrate with modern advisory data systems. This article summarizes the core research design types, methodological safeguards, and analytic approaches. Additionally, we discuss how SCR can be applied to financial planning contexts and outline a roadmap to close the research‐to‐practice gap by creating practice‐based evidence. An illustrative case demonstrates how practitioners can implement these methods in everyday practice.
Wery et al. (Tue,) studied this question.