Manualization of Occupational Therapy Interventions: A Crucial but Overlooked Step in Building Evidence

Manualization of an intervention is an essential component in the implementation of research studies. When collaborating on research teams, manualization gives a template to check for fidelity and thus determine if the intervention is carried out in the way in which it was intended by the program developers. Murphy and Gutman (2012) have outlined essential elements in intervention fidelity that are often absent from study descriptions. For example, within the intervention manual researchers should describe the intervention design to include the number, length, and frequency of intervention sessions. The researchers should explain both the theoretical framework and any clinical guidelines that provided the foundation for the intervention. The manual must also define the “active ingredients” or elements of the intervention proven to be responsible for changes in specific outcomes, often quite complex in intervention research. Careful consideration must be given to the training of individuals who will be implementing the study’s procedures. Implementation training is not only outlined in the manual, but the manual content can also be used for training purposes. Written/electronic intervention manuals can be an important tool to assist in fidelity as they provide a means to articulate the distinct differences of the intervention and ensure outcomes are replicated.

As an example of not only the clinical and research utility of manualization, but also the training benefits of manualization, we offer an example of a manualized, evidence-based group intervention for adolescents and young adults with autism. The Assistive Soft Skills & Employment Training program (ASSET) was developed by a group of interdisciplinary researchers from the fields of occupational therapy, rehabilitation counseling, and special education to address the need for improved employment outcomes among young adults with autism (Sung et al., 2018; Connor et al., 2019). ASSET is a group intervention consisting of 13 sessions guided by a facilitator manual, associated PowerPoints, and participant handout book. The ASSET group curriculum was developed, tested, and refined through a dissertation (Connor, 2017) and feasibility study (Sung et al., 2018) in which a sample of 17 young adults with autism and without intellectual disability participated in an 8-week, preliminary version of the program

Using mixed-methods, intervention researchers used pre- and postintervention surveys and interviews to assess program feasibility, user acceptability, practicality, and preliminary efficacy. Recruiting a sample of 17 young adults with autism is challenging, and effectively delivering the intervention could not be achieved in one large group. Thus, four intervention groups, with a range of 4-6 members per group, were run over a period of two years. Results indicated significant improvements in work-related social skills knowledge, social functioning, and social/empathy self-efficacy.

Weekly feedback from group participants and facilitators was used to refine and extend the intervention content and approach to an expanded 13-week training program. The intervention manual allowed for guidance during each of the four deliveries of ASSET. The manual provided the researchers assurance of fidelity during treatment implementation. Adherence to the treatment protocol through manualization provided a consistency that supported pooling of results for analysis. Moreover, the manual made it possible to train multiple co-facilitators to deliver the intervention, thereby decreasing researcher burden. Manualization was also instrumental in a follow-up study (Connor et al., 2019) in which we expanded the sample (n=26), delivered two additional group interventions, and examined psychological wellness in addition to social functioning and self-efficacy. Results indicated significant improvements in all previous outcomes with the addition of significant declines in anxiety and a trend toward decreasing depression.

Currently, our team is investigating the efficacy of having occupational therapy graduate students deliver ASSET as both a research and practicum experience. Once again, manualization was key. The manual not only ensures treatment fidelity, but is also used as a training manual for the students. Specific content in the intervention manual, including the PowerPoints, curriculum, and pre-planned activities, provide the students with structure and a place to start as they develop therapeutic use of self and group facilitation skills. In alignment with suggestions in the literature, students were also encouraged to flex and extend the curriculum (Blanche et al., 2011) to meet the needs of their particular groups. In addition, the journaling and note writing that students completed for fieldwork became another data source for the research. From a faculty perspective, the ability to serve as both research mentor and clinical instructor aided in the direct observation of fidelity along with the ability to assess the appropriateness of the manualized intervention as a training curriculum for students. Finally, use of the manualized ASSET curriculum ensured that students experienced how theory guides practice as they learned to measure outcomes and design activities targeting the key constructs of Social Cognitive Career Theory (Lent & Brown, 1996), the guiding theory underlying ASSET.

Noting that intervention manuals are not commonly used in occupational therapy, and recognizing that manualization is a necessary first step in designing research that can lead to the highest level of evidence (Blanche et al., 2011), we encourage researchers, students, and clinicians to collaborate on manualizing and testing occupation-based intervention programs. By beginning with manualization, and using a developmental iterative design to test the program, we have been able to validate and extend the ASSET program. In addition, we have used the manual as a training resource for our students, and are currently examining ASSET’s utility among other populations, including adolescents with substance use disorder. Perhaps, most notably, manualization makes it possible for us to conduct a future randomized controlled trial, the gold standard of intervention research, providing the highest level of evidence. We offer ASSET as an example of a fruitful collaboration between researchers, clinicians, and students in order to meet a need for evidence-based, replicable and extendable occupational therapy interventions.