This paper examines the utility of evidentiary pluralism, a research strategy that selects methods in service of content questions, in the context of rehabilitation psychology. Hierarchical views that favor randomized controlled clinical trials (RCTs) over other evidence are discussed, and RCTs are considered as they intersect with issues in the field. RCTs are vital for establishing treatment efficacy, but whether they are uniformly the best evidence to inform practice is critically evaluated. We argue that because treatment is only one of several variables that influence functioning, disability, and participation over time, an expanded set of conceptual and data analytic approaches should be selected in an informed way to support an expanded research agenda that investigates therapeutic and extra-therapeutic influences on rehabilitation processes and outcomes. The benefits of evidentiary pluralism are considered, including helping close the gap between the narrower clinical rehabilitation model and a public health disability model. KEY WORDS: evidence-based practice, evidentiary pluralism, rehabilitation psychology, randomized controlled trials Over the past two decades, medicine and then public health and the mental health professions have embraced the evidence-based practice (EBP) movement, which seeks to bring health care practices and policies in line with the best scientific knowledge (Brownson, Baker, Leet, & Gillespie, 2003;Goodheart, Kazdin, & Sternberg, 2006; Institute of Medicine [IOM], 2001Jenicek, 2003; Vitora, Habicht, & Bryce, 2004;Westen, Novotny, & Thompson-Brenner, 2004). Rising health care costs and the growth of managed care in the United States in the late 20 th century energized the early EBP movement, as did the rapid growth of the scientific knowledge base. The EBP movement is now an international movement that focuses on "evidence" as a guiding force in health care practice and policy. Although the concept of evidence remains at the heart of the movement, the nature and scope of the relevant evidence continue to evolve as EPB has expanded from its origins in acute medical care and drug therapies to encompass care for chronic health conditions and mental and substance use disorders. This paper is about that evolution and how it has affected Correspondence concerning this article should be addressed to Jalie A. rehabilitation psychology, sometimes in adverse ways, and why a broadened conception of evidence and the methods used to obtain it may be necessary for advancing the field.The early EBP movement emphasized the restrictive use of treatments that were "empirically validated" by a minimum of two randomized controlled clinical trials (RCTs) and used the findings as the basis for guidelines and manuals for best practices (Agency for Health Care Policy and Research, 1993;Chambless et al., 1996; Sackett, Strauss, Richardson, Rosenberg, & Haynes, 2000). RCTs came to be viewed as the "gold standard" of evaluation research and as superior evidence compared to non-randomized observat...