Recently, the World Association for Person-Centered and Experiential Psychotherapy and Counseling (WAPCEPC) has installed a Scientific Committee to promote empirical research to support the person-centered and experiential (PCE) approach. For this endeavor to be successful, traditional methods may not suffice. Because the majority of PCE psychotherapies intrinsically do not meet the requirements of standardization and generalization, they cannot (correctly) be included in Randomized Clinical Trials (RCTs). However, RCTs are still considered highly desirable for PCE therapies to qualify as Empirically Supported Treatment (EST), which in turn is decisive for being fully accepted (and covered) in mental health care. After briefly summarizing the ongoing discussion on the inherent limitations of RCTs in psychotherapy research, we describe some existing alternative approaches. Next, we advance a new large-scale and integrative research model that lets methodological pluralism take an essential place in providing robust evidence on both treatment outcome and the process of psychological change, which could be beneficial for PCE therapies. The essence of this suggested Wide Array Research Model (WARM) is a bottom-up strategy in which data are collected in a multitude of small, manageable, and low-cost modules. © 2013 World Association for Person-Centered & Experiential Psychotherapy & Counseling.