Journal for Person-Oriented Research 2017; 3(1): 28-48 Published by the Scandinavian Society for Person-Oriented Research Freely available at http://www.person-research.org DOI: 10.17505/jpor.2017.03 28 The Clinical Trials Mosaic: Toward a Range of Clinical Trials Designs to Optimize Evidence-Based Treatment Ty A. Ridenour 1,2 , Szu-Han K. Chen 3 , Hsin-Yi Liu 3 , Georgiy V. Bobashev 1 , Katherine Hill 4 , & Rory Cooper 3,5 1 Research Triangle Institute, International, Research Triangle Park, North Carolina 2 School of Pharmacy, University of Pittsburgh 3 Department of Rehabilitation Science and Technology, University of Pittsburgh 4 Department of Communication Sciences and Disorders, University of Pittsburgh 5 Human Engineering Research Laboratories, Department of Veterans Affairs Address Correspondence to: Ty A. Ridenour, PhD, MPE, Research Triangle Institute, International, 3040 E. Cornwallis Rd, PO Box 12194, Research Triangle Park, NC 27709-2194; phone: 919-248-8519; fax: 919-485-5555 Email address: TRidenour@rti.org To cite this article: Ridenour, T. A., Chen, S-H- K., Liu, H-S., Bobashev, G. V., Hill, K., & Cooper, R. (2017). The clinical trials mosaic: Toward a range of clinical trials designs to optimize evidence-based treatment. Journal for Person-Oriented Research, 3(1), 28-48. DOI: 10.17505/jpor.2017.03 Abstract Objective: Dichotomizing clinical trials designs into nomothetic (e.g., randomized clinical trials or RCTs) versus idiographic (e.g., N-of-1 or case studies) precludes use of an array of hybrid designs and potential research questions between these extremes. This paper describes unique clinical evidence that can be garnered using idiographic clinical trials (ICTs) to complement RCT data. Proposed and illustrated herein is that innovative combinations of design features from RCTs and ICTs could provide clinicians with far more comprehensive information for testing treatments, conducting pragmatic trials, and making evidence-based clinical decisions. Method: Mixed model trajectory analysis and unified structural equations modeling were coupled with multiple baseline designs in (a) a true N-of-1 pilot study to improve severe autism-related communication deficits and (b) a small sample preliminary study of two complimentary interventions to relieve wheelchair discomfort. Results: Evidence supported certain mechanisms of treatment outcomes and ruled out others. Effect sizes in- cluded mean phase differences (i.e., effectiveness), trajectory slopes, and differences in path coefficients between study phases. Conclusions: ICTs can be analyzed with equivalent rigor as, and generate effect sizes comparable to, RCTs for the purpose of developing hybrid designs to augment RCTs for pilot testing innovative treatment, efficacy research on rare diseases or other small populations, quantifying within-person processes, and conducting clinical trials in many situations when RCTs are not feasible. Keywords: Clinical trials, statistical analysis, trajectories, structural equations modeling, idiographic, nomothetic, treatment mechanisms, N-of-1, personalized medicine, pragmatic trials The decades-long debate pitting nomothetic research (aggregating group data to generalize results to populations) versus idiographic research (using short-term, intensive, time series data from individuals to reveal within-person processes) has renewed in psychology and healthcare (Cat- tell, 1952; Guyatt et al., 2000; Kratochwill & Levin, 2010; Molenaar, 2004; Nesselroade & Ghisletta, 2003; Shadish, 2014; Skinner, 1938). This debate is occurring primarily among statisticians, without consideration of evidence needed by clinicians and clinical researchers who stand to gain considerable rigor for treating clients/patients by an evolution in evidence-based, individualized treatment