This scoping review explored the range and characteristics of case study research within the occupational therapy evidence base from 2016 to 2021. A large number of studies (N = 88) were identified across a variety of practice settings and following a dip after 2016, publication trends appeared consistent over this period. This suggests that case study research has potential viability for contributing to the evidence base of occupation and health. However, the findings of this review identified inconsistencies in how case study research was defined and variation in the methodologies adopted. Therefore, to maximize its potential as an evidence building tool, further clarity on case study methodology is needed. It is hoped that this review, in particular the proposed definition and conceptual model, will help achieve this.
A key issue highlighted was the lack of consistent or easily identifiable terms used to describe the methodology. Some studies defined the design by number of cases (e.g. single/multiple), by purpose (e.g. exploratory, descriptive, experimental) or by data collection (e.g. quantitative, qualitative, mixed). Other terms were also used such as ‘almost experimental’, ‘case series’, ‘changing criterion’ and ‘case report’. Hyett (17) suggested case study, as a research approach, has been confused with the non-research based case report and this is supported by the findings of the current review. Self-identified ‘case studies’ were excluded, in line with the inclusion criteria, if they did not report data collection or analysis. In addition, journal classification of study type was at times incongruent with the methodology taken e.g. Proffitt et al (62). Alpi & Evans (112) highlight this lack of distinction not only in journal classification but also in database indexing. They propose that case study is a rigorous qualitative research methodology and case report is a patient or event description. Based on this, the Journal of Medical Library Association updated classification of descriptive manuscripts previously known as case studies to case reports and case studies as a research methodology are now identified as original investigations. Despite this effort at clarification, there is still room for debate. Where Alpi & Evans (112) suggest N-of-1 single subject studies fit the case report label, Paparini et al (10) aligns this to the explanatory case study. Therefore, this review adopted Yin’s (14) term ‘case study research’ as a common language that can be used by occupational therapists in the conduct and reporting of this methodology. It is suggested this will make the distinction clear from case report or non-research.
The issues highlighted in this review reflect current debate about case study research methodology. A key issue identified with empirical case study research was the inadequate description of the case and boundary so that it could be easily identified by the reader. Other reviews of case study research in occupational therapy included in this review (32, 39, 110) also identified this as a concern pre-2016 and Hyett (17) identified this more broadly in the literature, but particularly a concern for health and social science case studies. A clearly identifiable case, with detailed description including the boundary and context is necessary for practitioners to understand how it may translate to their own practice. A case is not synonymous with participant and, whilst it can be an individual of interest, it can also take a more intangible form of a process such as intervention delivery, practice networks or other practice areas of interest such as theory.
As a form of inquiry, case study research provides context specific, practice-based evidence, so the practice context must be understood. This in-depth, contextual understanding provides an alternative to studies seeking breadth of knowledge or generalizations and is thus the unique characteristic of case study research (11). For this reason, ‘in-depth’ inquiry and ‘occupational therapy practice context’ are positioned at the core of the proposed descriptive model, encapsulated by the ‘case and context boundary’ as essential elements to case study research methodology (Fig. 6).
Case study research has been shown to be a flexible methodology both in design and purpose. Of particular interest to evidence building, is its use to explore the efficacy and feasibility of an intervention in the real-life practice context. These findings support the assertions of previous authors who have suggested that case study research can be used to demonstrate clinical impact of interventions and to investigate complex multifactorial phenomena (11, 27–29). Particularly in areas of innovative or emerging practice, case study research can provide a way to capture impact when participant numbers or resources are not available to conduct larger scale inquiry. Stickley and Hall (48) for instance, specifically state that their study is the first known investigation into social enterprise in occupational therapy. As a first step to building evidence, a descriptive or single case account can therefore provide an important grounding on which to build upon. The need for timely evidence during the Covid-19 pandemic demonstrated an acute awareness of this but it has also been recognized as a process of cumulative evidence building in occupational science (113) and more broadly across other disciplines (114). Of note however is Flyvbjerg’s (16) argument that the case study holds value beyond pilot or preliminary data. Whilst it may be difficult to generalize from a case study, particularly in terms of process, the outcomes can contribute to knowledge when used to test a theory or data pooled across cases.
By mapping the findings of this review, case study research appears to mirror the broad and varying nature of occupational therapy. It reflects occupational therapy as a direct service provided to individuals or groups, but also to others on a client’s behalf (115). Organization, population and system level practice is also recognized as an important aspect of occupational therapy practice (33) and was reflected in the included cases (68, 75). Case study research therefore not only has the potential to evidence impact through intervention outcomes, but also has wider health and wellbeing impact potential by exploring and advocating for occupational therapy across the full spectrum of practice including diverse areas.
Occupational therapy was provided in a range of settings including hospital, community and industry sectors. Interventions adopted illustrate the global variation in occupational therapy practice. For instance, compression bandaging (82, 109) and electrical stimulation (64, 65, 116) are not aspects of standard practice in the UK but reflect other international practice standards (117, 118). Interventions were wide ranging and reflective of those described in the American Occupational Therapy Process and Domain Framework (33). This included therapeutic use of occupation (74), interventions to support occupation (119), education and training based (120) advocacy based (87) group based (121) and virtual interventions (122). Narrowing the intervention to a single entity was not always possible or appropriate reflecting the complexity of occupational therapy practice and several authors, for example Kearns Murphy & Sheil (51) and Pretorious (91) instead reported occupational therapy as the intervention involving a range of activities and approaches that were meaningful and goal directed for the client.
A suggested strength of case study research identified by the findings, is the similarity between the research process and clinical practice. Fleming (123) had suggested that practitioners generate hypothesis in clinical practice to test theory and problem solve elements of the therapy process for example, why an intervention may not be working as expected. Similarly, case study research has been used to test theory in evaluative or explanatory designs. Methods of data collection (e.g. observation, outcome measurement, document review, interview, client feedback) and analysis (e.g. descriptive, visual, pattern-matching outcomes) bear resemblance to how evidence is collected in practice to inform the intervention process (124). The term ‘pattern-matching’ is an analytic strategy adopted by Yin (14) in case study research to compare patterns in collected data to theory. However, pattern matching is also evident in occupational therapy clinical reasoning literature, particularly in relation to how practitioners utilize tacit knowledge to inform decision making (125, 126). This insight into case study research supports the perspective that it may be a more familiar and therefore achievable approach to evidence building for practitioners.
The challenge of capturing the complexity of practice has previously been cited as a barrier to research engagement and evidence-based practice in occupational therapy (38). In contrast to this, case study research was largely justified as the chosen methodology because it allowed for individual tailoring of the intervention to the case and context (59, 84, 86). The ability to provide a narrative description of the case, context, intervention and how it was implemented or adapted was seen across case study research, including single case experimental designs (SCED). This idea of ‘individualization’ of treatment is also noted by Fleming(127) to differentiate occupational therapy clinical reasoning from medical procedural reasoning. The effectiveness of occupational therapy is not solely based on a prescriptive treatment, but is also influenced by the interactions between the therapist and service user and the particulars of that context. Therefore, if thinking on clinical reasoning has evolved to capture the important nuances of interactive reasoning(123) and furthermore embodied practice(126) then it would seem appropriate that the research approach to building evidence should also. A pluralistic approach whereby there is a valued position for both case study research and larger scale inquiry to capture both the depth and breadth of practice would seem fitting. Collecting and pooling case study research data from practice can capture these important elements and allow for pattern matching or synthesis. In this way, case study research can hold value for evidence building, just as the randomized controlled trial, or other larger scale inquiry, does for generalizability with the potential to inform policy and practice.
Based on the findings from this review, collecting case studies from practice to develop an evidence base is potentially viable given its uptake across practice areas and relatively consistent publication. In psychotherapy, Fishman (23) advocated for a database of cases which follow a systematic structure so they can be easily understood, recognized and data compared. Journals dedicated to publishing case data using a methodical format have since evolved in psychotherapy (128). In occupational therapy, the Japanese Association of Occupational Therapists (129) collects practical case reports from members using dedicated computer software to host a collective description of occupational therapy practice. There is potential then to adopt this even on an international basis, where occupational therapy practice can be shared and measured. The challenge however, is in achieving a systematic approach to how case study research data is collected and recorded to allow for meaningful comparisons and conclusions to be drawn.
In this review, quantitative and mixed method designs used a range of different outcome measures which is not conducive to pooling cross case data. Goal Attainment Scaling (GAS) is an outcome measure that defines individualized goals and relative outcomes to determine therapeutic effectiveness (130). It is a measure advocated for its applicability across areas of practice but also for research, both large scale inquiry and case study research (131). In this review, it was used across age groups, in the community, outpatient settings and schools and in the areas of neurodevelopmental disorder, stroke, brain injury and ill mental health.
Kearns-Murphy & Sheil (51, 131, 132) adopted Goal Attainment Scaling in their longitudinal case study and explored the different methods of analysis of the measure. They concluded that charting GAS scores at multiple timepoints is beneficial to case study research as it adds to the ‘in-depth’ analysis providing insight into the fluctuations of therapy and outcomes in the real-life context. Visual analysis of charted scores is then an appropriate analytic technique for intervention-based case study research. Two time points, before and after, is more suited to large scale inquiry for generalization but in the case study, only the performance of an individual on a particular day is highlighted which may be influenced by several contextual factors. Given these assertions, adopting a consistent outcome measure across practice such as GAS, would allow for in depth, case and context specific understanding that could also be comparable and pooled across cases.
Strengths and limitations of the scoping review
This review searched published and grey literature using a variety of terms that have been used interchangeably with case study research with the aim of conducting a comprehensive overview. It followed a peer reviewed protocol with systematic and transparent processes. JBI methodology for the conduct of scoping reviews was followed and bibliographic software (Mendeley) and systematic review software (Rayyan) was used to manage citations and the screening process. Additionally, an updated search was completed in July 2021 to enhance the timeliness and relevance of findings.
Ten databases were searched and no further relevant articles were identified through websites or citation searching, affirming that a thorough search had been conducted. However, to balance a comprehensive search with the practicality of resources, some decisions were made which may impact the inclusivity of the review. Western dominant databases and English language limits were applied because of translation resource availability within the research team. The search algorithm was developed and tested with an academic librarian at the protocol stage however, as case study methodology was not always clear from the title and abstract, an unmanageable amount of data was presented at full text stage. To manage the number of records, inclusion criteria was changed to provide a contemporary overview from 2016 rather than 1990. This may introduce some bias to the review, where relevant articles pre-2016 or in other languages were omitted. However, the narrower focus allowed for in-depth data mapping to maximize the value of findings for informing future practice and research. Without taking this step, the output would likely have been more superficial. As a large number of 88 studies were still included in total, it was felt an appropriate balance had been achieved.