In 2011, the American Occupational Therapy Foundation (AOTF) and the American Occupational Therapy Association (AOTA) identified the development of a taxonomy to uniformly describe occupational therapy and rehabilitative interventions as a major research goal, necessary for advancing the science of occupational therapy and working toward the AOTA’s Centennial Vision (AOTA & AOTF, 2011). The research priorities included advancing the development and use of theory-driven, manualized interventions.

Although the Occupational Therapy Practice Framework: Domain and Process (3rd ed.; OTPF–3;AOTA, 2014, p. S15) provides an excellent description of occupational therapy practice domains, its purpose is not to depict features of interventions as envisioned by this 2011 directive. Similarly, the International Classification of Functioning, Disability and Health (World Health Organization, 2001) characterizes domains of human function that describe desired treatment outcomes (e.g., coordination of voluntary movements, preparing simple meals), but it is insufficient for specifying the individualized treatments delivered by clinicians (Dijkers et al., 2014; Hart et al., 2014).

Clinicians and researchers currently lack a standardized approach to describe interventions, and we assert that clear specification of the content and process of interventions would benefit practice, research, and education. In this article, we discuss development of the Rehabilitation Treatment Specification System (RTSS), previously known as the Rehabilitation Treatment Taxonomy, which uses a theory-driven and systematic approach to define, specify, and quantify rehabilitation treatments. Although this framework is designed for use by all rehabilitation professions, we focus on the potential benefits for occupational therapy practice.

Current health care reforms in the United States are focused on reimbursement for value and high-quality care instead of volume of services (U.S. Department of Health and Human Services, 2015). Quality care means “doing the right thing, at the right time, in the right way, for the right person—and having the best possible results” (Agency for Healthcare Research and Quality, 2003, para. 1). The problem for all rehabilitation disciplines is that doing the right thing requires a standard method to identify all treatments; research on the benefits of all treatments; comparative effectiveness research for selected treatments; and dissemination of research evidence to practitioners in formats that they can access, understand, and use.

Because clinicians and researchers currently cannot specify treatments in a way that affords examination of why patients improve, they cannot sufficiently explain which treatments are effective, for which patient groups, and in what time frame or dosages. Moreover, many practice guidelines do not adequately describe how to deliver the interventions (McDonald et al., 2007). These factors may affect quality of care through inefficient care coordination and inconsistent treatment, both within a care facility and across the care continuum.

Because of the emphasis on health outcomes and the wide scope of rehabilitation, examining efficacy and effectiveness of interventions will require extensive effort, costs, and time. A comprehensive method to systematically describe interventions will enhance practitioners’ ability to examine therapeutic change and identify causal mechanisms. Elements of interventions provided in “usual care” are frequently ill defined, which is problematic for comparative effectiveness research and systematic reviews (McDonald et al., 2007). Clinicians and researchers need to clearly identify elements of their interventions to develop treatment protocols, replicate successful treatment programs, and compare treatment outcomes across patients and facilities.

As professions are being pressed to explicate how they contribute value to patient outcomes (DeJong, 2016), they will need tools to examine similarities and differences of treatments delivered across rehabilitation disciplines. Although documentation formats capture the amount of time spent in delivering treatments and may describe the focus of interventions, they do not convey details about the practitioner’s actions or rationale for interventions. Given these practice and research challenges, we recommend a theory-driven framework to explicitly describe the process of clinical reasoning and treatment of all rehabilitation disciplines, including occupational therapy.

The RTSS is a systematic method to describe the treatments delivered across treatment settings. Per the RTSS, clinicians begin the treatment planning process after evaluation by identifying a target for intervention and selecting treatment ingredients on the basis of their known or presumed mechanisms of action. These three elements (target, ingredients, and mechanism of action) comprise a treatment component (Figure 1). A target is the proximal, functional change that is intended to be brought about by the treatment. It is measurable, at least in principle. Treatment ingredients are what a clinician does, says, or delivers when working with a patient (e.g., instructions, materials, assistance). The mechanism of action, although not always observable, is the known or hypothesized process of change. The practitioner’s prediction of the mechanisms that will effect change, on the basis of experience or research evidence, contributes to the selection of ingredients used in treatment.

The RTSS distinguishes between treatment theory, which explains the changes in targets of intervention, and enablement theory, which explains more distal outcomes or aims. Enablement theory is concerned with the relationships among various impairments, activity limitations, and participation restrictions (Whyte & Barrett, 2012). For example, an outpatient occupational therapy session may have a target of increased independence when using public transportation by having the patient learn by doing (e.g., correctly read the schedule, locate the bus stop, manage his or her time), as stated by treatment theory. The aim of the intervention—for example, resuming his or her role as a library volunteer—will require additional skills, such as social interaction, problem solving, and community mobility, as predicted by enablement theory. These two theories are helpful when deconstructing complex interventions into their individual parts (treatment theory) and analyzing the many factors that contribute to participation gains (enablement theory). The RTSS’s explicit focus on treatment theory helps to distinguish and describe the treatment components of occupational therapy interventions.

Three distinct groups of treatment components are mutually exclusive with respect to their targets, mechanisms of action, and select ingredients: (1) the Organ Functions group components seek to effect changes in the functions of organs or organ systems; (2) the Skills and Habits group includes the development of skills and habits, typically through repeated practice; and (3) the Representations group components aim to bring about changes in knowledge, attitudes and beliefs, or changes in volition.

A contribution of the RTSS is its emphasis on distinguishing features of the therapeutic process that address the development of skills and habits from knowledge acquisition. For example, the RTSS scheme can separate direct targets of treatment to improve skills and habits (e.g., routine performance of weight shifting in wheelchair) from knowledge targets (e.g., understanding of the causes of skin breakdown). Occupational therapy practitioners select ingredients (e.g., practicing weight shift in wheelchair, educational materials about wounds) to address these targets. Therefore, the RTSS framework conveys the complexity of person-centered treatments delivered by all rehabilitation clinicians. For more in-depth information and clinical and research implications of the RTSS, readers are referred to a special issue of the Archives of Physical Medicine and Rehabilitation (Hart et al., 2018; Van Stan et al., 2018; Whyte et al., 2018; Zanca et al., 2018).

The breadth and diversity of rehabilitation treatments contribute to the difficulty in clearly articulating the content and process of patient care. We maintain that using a specification scheme to describe treatments can improve clinical practice through better clinical reasoning and better selection of targets and ingredients for all treatment components; provide a means to answer theory- and practice-based research questions; and assist students and practitioners in refining the art and skills of clinical reasoning. The implications for occupational therapy practice, research, and education follow.

As a first step, theory-based specification rules may facilitate clinical practice and interprofessional communication through comprehensive description of treatment components. Clinicians can examine well-described targets and ingredients, and presumed mechanisms of action, when reflecting on patient progress or lack of progress. Clear specification of treatments using this systematic framework can improve communication within and across rehabilitation settings and during transitions of care. For example, if the covering occupational therapy practitioner, unfamiliar with the patient, reads “Practice activities of daily living—dressing, tub transfer,” he or she will not know which treatment targets (e.g., improved sequencing or balance skills) to emphasize. When occupational therapy practitioners carefully delineate treatments, the consistency of treatment after hand-offs to another occupational therapy practitioner or another facility may increase. As a result, clinical efficiency may improve, potentially enhancing the patient’s health care experience. In summary, a specification scheme can help clinicians better tailor interventions for individual patients as a step toward doing “the right thing.”

Although research examining the effects of occupational therapy interventions has grown significantly, clinicians and researchers continue to lack strong support for one intervention over another. This evidence gap may stem in part from the need for a theory-driven approach to examine the therapeutic change process. Regardless of the theory used to guide intervention, the RTSS’s method for specifying intended targets and suitable treatment ingredients (e.g., dosing parameters, clinician cueing or feedback, use of adapted equipment) will improve the ability to examine how the active ingredients affect the target of intervention. Dissecting interventions via this conceptual scheme could reveal that modified treatments differ from the original protocol in key characteristics and thus may not effect change in the same way. The RTSS can inform intervention research by guiding manualization and setting the stage for comparative effectiveness studies.

Education of the next generation of clinicians has increasingly focused on theory- and evidence-based interventions (Fleming-Castaldy & Gillen, 2013). That theory-driven models to facilitate the development of students’ clinical reasoning skill are integrated into academic programs is essential. The RTSS framework can help students link clinical theory to specific actions (ingredients) by facilitating discussion regarding the treatment targets and details of intervention delivery. Active learning experiences during case studies and client simulations can engender habits of clearly describing treatments and evaluating the fit between ingredients and targets. The RTSS provides the structure and terminology to depict how the ingredients can be modified on the basis of patient performance. Students fortified with the RTSS will be better equipped to examine and understand the process of therapeutic change. Use of the RTSS by students, researchers, and clinicians has strong potential to improve the science and delivery of occupational therapy practice.

To illustrate how the RTSS can be used to more precisely describe treatments, we present the following clinical case example:

Using the RTSS, we describe selected treatment components delivered to Bill and his spouse during inpatient rehabilitation (Table 1). The treatment ingredients include preparatory tasks to treat Organ Functions targets, as well as purposeful activity and occupation-based interventions, in concert with the OTPF–3, to address Skills and Habits or Representations targets. Practitioners typically identify multiple targets and ingredients to address patient-centered goals (aims, in RTSS terminology). We recognize identifying the mechanisms of action can be challenging. Many interventions to address Skills and Habits targets involve “learning by doing,” which includes mechanisms of “learning, adaptation, coping, and feedback loops supported by neural or behavioral plasticity” (Hart, 2009, p. 825). The RTSS prompts occupational therapy practitioners to more carefully describe how their interventions may promote change in targets and can assist the profession in communicating the content and process of patient care.

In a project funded by the Patient-Centered Outcomes Research Institute, an RTSS manual was created to provide clinicians, researchers, and educators with a framework for describing treatments according to their targets, mechanisms of action, and active ingredients (Whyte, 2018). The manual presents guidelines to specify treatments delivered by all rehabilitation disciplines and includes examples from clinical practice scenarios.

The priorities for intervention, translational, and health services research set forth by AOTA and AOTF (2011)  have stimulated research on the content, process, and outcomes of occupational therapy interventions. Future development of the RTSS can contribute to research, education, and clinical practice efforts through better characterization of rehabilitation interventions. This common framework and language will stimulate a deeper discussion of treatment targets and ingredients and will set the stage for improved clinical reasoning, care coordination, and comparative effectiveness research.

The research reported in this article was partially funded through Patient-Centered Outcomes Research Institute (PCORI) Award ME-1403-14083. The statements in this article are solely the responsibility of the authors and do not necessarily represent the view of PCORI, its board of governors, or its methodology committee. We thank Marcel Dijkers, Tessa Hart, John Whyte, and Christine Chen for their thoughtful comments and suggestions during the preparation of this article.