1: Introduction to Intervention Research

Introduction to Intervention Research

Clients experience health problems and seek assistance from health professionals to address these problems. Health professionals are responsible for providing high‐quality healthcare that successfully manages the clients’ problems and promotes their well‐being. Specifically, health professionals are expected to engage with clients in making treatment‐related decisions; provide the selected treatment or intervention; monitor clients’ responses to treatment, that is, changes in the experience of the health problems; and adapt the intervention, as needed, to clients’ responses. Thus, interventions constitute the central elements of healthcare, and their careful selection and appropriate delivery form the basis of high‐quality care. Sound decision‐making demands that health professionals: are aware of available interventions addressing the health problem with which clients present and of evidence regarding the benefits or effectiveness and the risks or discomfort associated with alternative interventions; inquire about clients’ values and preferences; and collaboratively choose the intervention that is beneficial yet consistent with clients’ values and preferences. Intervention research is concerned with generating evidence on the benefits and risks of health interventions, to inform treatment decision‐making in practice.

What constitutes empirical evidence that is useful in informing treatment decisions in practice is evolving. With the adoption of evidence‐based practice in the early 1990s, evidence from randomized controlled or clinical trials (RCTs), also known as experimental designs, was admitted as the most reliable or robust evidence of health interventions’ benefits; the RCT is believed to have features that enhance the validity of inferences regarding the causal impact of interventions on outcomes (Holm et al., 2017). Consequently, evidence synthesized across RCTs was relied on to generate guidelines that inform decision‐making in practice.

In the past decades, experiences with evidence‐based practice revealed limitations of this approach to healthcare (Horwitz et al., 2017). These limitations, along with increasing societal value and demand for person‐centeredness, are contributing to shifts in perspectives on what constitutes high‐quality healthcare and what methods and strategies are appropriate for the design, delivery, and evaluation of interventions.

In this chapter, the treatment decision‐making steps and the information needed to guide decision‐making in practice are briefly reviewed. Limitations of evidence derived from RCTs in informing decision‐making in practice are highlighted and related to disregarding the principles of client‐centeredness and the complexity of the real world. Advances in research methodology that account for complexity are introduced. The overall process for designing, delivering, and evaluating interventions, and implementing them in practice, is briefly described.


Health professionals (i.e. practitioners, clinicians, therapists) include nurses, physicians, psychologists, dietitians, health educators, and allied health therapists such as respiratory, physical, occupational, and speech‐language therapists. They work independently and collaboratively to provide high‐quality healthcare to individuals, families, and communities (hereafter collectively referred to as clients) in a range of settings such as primary, home, acute, rehabilitation, and long‐term care.

Provision of high‐quality healthcare aims to: promote health; prevent and manage health problems; prevent complications; and maintain or improve well‐being. Currently, person‐, patient‐, or client‐centered care is viewed as the cornerstone of high‐quality care (Van Belle et al., 2019), and client participation in treatment decisions and in health management as the pillar of client‐centered care (Britten et al., 2017). Client participation is enacted in shared decision‐making. Shared decision‐making is an interactive process that involves collaboration between clients and health professionals, focused on making treatment decisions (Stacey & Légaré, 2015). The application of shared decision‐making in practice involves several steps (Coutu et al., 2015; Elwyn et al., 2014; Muscat et al., 2015; Shay & Lafata, 2014):

  1. Health professionals conduct a comprehensive and thorough assessment of clients’ condition. The assessment covers all domains of health, including biophysiological, physical, cognitive, emotional, behavioral, sociocultural, and spiritual domains, as well as the clients’ personal account of the health problem and its impact on their life.
  2. Health professionals critically analyze the findings of the assessment and, together with the clients, formulate the clients’ health needs, that is, the potential (i.e. at risk) and actual health problems with which clients present and requiring remediation; in addition health professionals work with clients to prioritize their problems. An in‐depth and lucid understanding of the clients’ health problems is necessary for selecting the remediation interventions.
  3. Health professionals appraise alternative interventions; discuss with the clients the benefits and risks of the interventions; elicit clients’ preferences for interventions; and collaboratively select the most appropriate, effective, and safe ones.
  4. Health professionals deliver the selected interventions for, on behalf, or with clients.
  5. Health professionals and clients monitor clients’ status on a regular basis to determine the extent to which the interventions were successful in addressing clients’ health problems. If unsuccessful, health professionals and clients investigate factors that may influence the effectiveness of the interventions and should be accounted for in adapting the same interventions or providing alternative ones.

The application of decision‐making in practice requires a sound theoretical and empirical knowledge base of the health problem and the interventions. This implies that health professionals have access to:

  1. A conceptualization of the health problem with which clients present. The conceptualization clarifies the nature of the problem; specifies its indicators; presents a comprehensive list of its determinants experienced in different domains of health and at different levels (e.g. interpersonal, environmental); and delineates the relationships between the health problem and other co‐occurring problems, which are likely to be observed with the increasing prevalence of multiple chronic conditions, particularly among older adults (Golfam et al., 2015). The conceptualization helps health professionals understand the clients’ health problem and overall condition, which, in turn, guides the search for relevant interventions.
  2. A conceptualization of alternative (if available) interventions addressing the same health problems. The conceptualization describes the components and activities comprising each intervention, and explains its mechanism of action (i.e. why and how the interventions work in addressing the health problem). This conceptualization is important for understanding the interventions and for adapting them to the clients’ context or life circumstances (Levinton, 2017). Health professionals find it difficult to apply interventions they do not understand (Kazdin, 2007).
  3. Empirical evidence that indicates the extent to which each alternative intervention is effective and safe in addressing the health problem, as well as its relative effectiveness (i.e. compared to other interventions).

Empirical evidence on the effectiveness of interventions has been regarded as a credible source to inform health professionals’ practice and to guide decision‐making. It forms the foundation of evidence‐based practice.


Evidence‐informed or evidence‐based practice refers to “the conscientious, explicit, and judicious use of current, best evidence in making decisions about the care of individual patients” (Sackett et al., 1997, p. 2). Proponents of evidence‐based practice believe that interventions, evaluated in the context of research studies and found effective and safe, can be delivered in the same and consistent manner to produce the same effects in clients presenting with the same health problem, under the conditions of day‐to‐day practice. They advocate the development of guidelines to inform practice. Guidelines consist of systematically developed statements about recommendations for interventions that have demonstrated effectiveness and can be used to address a health problem, and procedures for monitoring the intervention’s outcomes. The guidelines are disseminated to health professionals who are expected to implement the recommended interventions (Fernandez et al., 2015).

Proponents of evidence‐based practice developed a hierarchy of research designs that are most appropriate for generating evidence on the effectiveness of interventions. They place high value on evidence derived from primary or meta‐analytic studies that used the RCT design to investigate the effects of interventions. The RCT is deemed the most reliable, even the “gold standard” for intervention evaluation research because its features are believed to minimize potential biases. Controlling for biases is required for demonstrating the causal effects of the intervention on outcomes (Hansen & Tjørnhøj‐Thomsen, 2016; Holm et al., 2017).

To date, experiences with evidence‐based practice have been less than optimal. It is estimated that up to 55% of clients receive interventions recommended in guidelines for acute, chronic, and preventive healthcare, and if provided, wide variations in implementing the evidence‐based interventions were observed (Greenhalgh et al., 2014; Harris et al., 2017). Several factors related to the characteristics of the healthcare system, organization, health professionals, clients, and the interventions affect the implementation of evidence‐based interventions and guidelines in daily practice (Lau et al., 2016). Evidence suggests that health professionals do not depend on research as a source of information to guide practice. Rather, they rely on other sources, primarily clinical knowledge either gained personally or shared by colleagues, as well as client experience (Spenceley et al., 2008).

Recently, concerns have been raised about the applicability of evidence, derived from primary and meta‐analytic studies using the RCT design, in informing practice (Ioannidis, 2016). Overall, the concerns stem from limitations of the RCT design in generating evidence that is relevant to the practice context (Braithwaite et al., 2018; Reeve et al., 2016). The limitations are related to the features of the RCT (i.e. careful selection of participants, random assignment, standardized delivery of treatment) that enable the focus on the direct causal effects of an intervention on outcomes and the control of potential sources of bias. As such, the RCT features ignore the complexity of the real world, the individuality of clients’ experiences of the health problem and life circumstances as well as responses to treatment, and clients’ participation in treatment decisions.

Careful selection of participants confines the RCT sample to a select subgroup of the target client population (e.g. clients with no comorbid conditions), which limits the applicability of the findings to other subgroups of clients seen in practice (Greenhalgh et al., 2014). Random assignment of participants to treatment groups does not reflect the treatment decision‐making process followed in practice. Therefore, random assignment is not well received by clients participating in the RCT (thereafter referred to as participants) and has been found to affect enrollment in the trial, attrition and nonadherence to treatment, which weaken the validity of inferences regarding the effectiveness of an intervention (see Chapter 14). Standardized delivery of interventions is not responsive to clients’ individual experiences, life circumstances, and preferences. Standardization also is difficult to transport into practice due to the complex and inter‐related influence of factors pertaining to clients, health professionals, and context (Chu & Leino, 2017; Leask et al., 2019). The focus on the average direct causal effects of the intervention ignores individual variability in clients’ responses to treatment (i.e. level of improvement in outcomes observed following treatment completion) and the mechanism through which the treatment produces its benefits; yet, health professionals need to understand what client subgroups respond favorably to the intervention and how the intervention produces its benefits for making appropriate treatment decisions (Horwitz et al., 2017; Lipsitz & Markowitz, 2013; Van Belle et al., 2016).

The limitations extend to meta‐analytic studies or systematic reviews of RCT findings, which form the basis for recommendations stated in guidelines. Attempts at synthesizing RCT‐derived evidence face challenges associated with limited replication (e.g. Pereira & Ioannidis, 2011). Limited replication is manifested in conflicting and, therefore, inconclusive evidence of the intervention’s effectiveness (Hesselink et al., 2014). Accordingly, the guidelines’ recommendations are usually stated in general terms that simply identify the interventions that can be used in addressing a health problem (Edwards et al., 2007). In addition, reports of primary and meta‐analytic studies as well as guidelines provide a brief description of the interventions. Insufficient description of the interventions constrains their replication and proper implementation in research and practice (Bach‐Mortensen et al., 2018; Levinton, 2017). For instance, Glasziou et al. (2010) found that health professionals were able to replicate the interventions evaluated in half of 80 studies published in the journal of Evidence‐Based Medicine. Furthermore, the guidelines do not offer instructions on how to adapt the design and delivery of interventions in a way that preserves their active ingredients yet is responsive to the characteristics, preferences, and life circumstances of clients and to the resources available in local practice contexts (Bach‐Mortensen et al., 2018; Westfall et al., 2009).

Accordingly, the evidence generated in primary and meta‐analytic studies using the RCT design is of limited utility in informing practice. It does not address the questions that health professionals ask when making treatment decisions (Bonell et al., 2018; Levinton, 2017). The questions include:

  • Who (i.e. clients with what sociodemographic and health or clinical profiles) most benefit (i.e. demonstrate improvement in outcomes) from an intervention, delivered in what mode and at what dose?
  • What are the intervention’s active ingredients (operationalized in what specific components) responsible for its benefits?
  • What risks or discomforts are associated with the intervention?
  • How and why does the intervention work to produce its benefits? Or, what is the mechanism of action responsible for the intervention’s effectiveness in addressing the health problem?
  • What resources are needed to deliver the intervention?
  • What contextual factors influence the delivery of the intervention by health professionals, its uptake and enactment by clients, and its effectiveness?
  • To what extent and how can the intervention be tailored to the individual clients’ characteristics or preferences, and/or adapted to the local practice context?
  • What alternative interventions are available to address the health problem, and what are their relative benefits (effectiveness) and risks (safety)?

Intervention research needs to be reoriented toward developing well‐conceptualized yet practice‐relevant interventions, and generating the evidence that addresses these questions. The goal is to consolidate the theoretical and empirical knowledge that informs practice, and ultimately improves the quality of healthcare and the health of clients. To be useful in informing practice, intervention research should embrace a realist, pragmatic perspective in reflecting the characteristics of practice: client‐centeredness and complexity. This can be achieved through client engagement and use of a range of relevant research designs and methods.


The less‐than‐optimal experiences with evidence‐based practice, the limited applicability of RCT‐derived evidence to practice, in combination with clients’ demand for an approach to healthcare that reflects their individuality, values, and preference, have led to the resurgence of client‐centered care as the “core” of high‐quality healthcare (Beck et al., 2010; de Boer et al., 2013; Sidani & Fox, 2014; Van Belle et al., 2019; Vijn et al., 2018).

Client‐centeredness is an approach to healthcare familiar to health professionals. Professionals are instructed, socialized, and expected to deliver client‐centered care. Client‐centered care is applied at different levels. At the individual level, it involves the application of tailored and adaptive interventions addressing the presenting health problem or aiming to change health behaviors (Hekler et al., 2018) and personalized or precision medicine (Bothwell et al., 2016). At the group level, client‐centeredness is illustrated by family‐centered care or the provision of health interventions that are adapted to the demands and preferences of particular communities such as ethno‐cultural communities (Barrera et al., 2013; Netto et al., 2010). At the healthcare organization level, client‐centeredness involves the adaptation of evidence‐based interventions and practice guidelines to the local context (Harrison et al., 2010; Powell et al., 2017) and at the system level, it is reflected in patient engagement (McNeil et al., 2016).

In general, the application of client‐centered care involves: (1) a comprehensive and thorough assessment of the clients’ condition to identify their health problems, beliefs, values and preferences; (2) collaboration and active participation of clients in prioritizing their problems, designing new or selecting available, evidence‐based interventions, and implementing the selected interventions (as is done in shared decision‐making); and (3) adaptation or tailoring of the intervention for consistency with clients’ problems, beliefs, values, and preferences, as well as with their changing experiences of the health problem, and life circumstances, over time.

Cumulating evidence supports the benefits of client‐centered care. At the individual level, client‐centered care was found to improve clients’ knowledge of their condition and treatment, experiences with healthcare, general health and well‐being. It also enhanced adherence to treatment; self‐efficacy in managing the health problem; and reduced health services use and cost (Barello et al., 2012; Fors et al., 2018; Hibbard & Greene, 2013; Ren et al., 2019; Vijn et al., 2018). Similarly, tailored interventions were reported to be more effective than non‐tailored ones (Hawkins et al., 2008; Richards et al., 2007). At the community level, providing culturally tailored interventions was associated with increased client satisfaction but not with improvement in health outcomes (Renzoto et al., 2013). At the healthcare organization and system level, client‐centered care contributed to the development of new and improved services (Mockford et al., 2012).

The provision of client‐centered care, the cornerstone of high‐quality healthcare (Van Belle et al., 2019), requires the availability of interventions with demonstrated appropriateness, acceptability, effectiveness, safety, and efficiency. Appropriate interventions are logical, reasonable, and sound treatments that address a specific health problem. This implies that the nature of the interventions, reflected in its active ingredients, is consistent with the nature of the health problem.

Acceptable interventions are desirable by clients expected to receive the interventions. Desirable interventions are perceived as consistent with the clients’ beliefs about the health problem and its treatment, suitable to their lifestyle, safe and convenient to apply in their daily life (Sidani et al., 2018). Related to acceptability is the notion of cultural relevance of interventions; it refers to the congruence of the interventions’ components, mode and dose of delivery, with the beliefs, values, and norms held by particular groups or ethno‐cultural communities (Barrera et al., 2013). Effective interventions produce the best health outcomes by activating the anticipated mechanism of action (Dalkin et al., 2015); that is, they induce changes in clients’ cognition, skills, or behaviors that mediate improvements in the experience of the health problem, health, and well‐being. Safe interventions are associated with no or minimal risks or discomfort (Bonell et al., 2015). Efficient interventions are optimized in terms of content, delivery, and resources required for their implementation, to maximize health outcomes; that is, they yield the highest impact (i.e. large improvement in the outcomes in a large proportion of the population) within a reasonably short time period (i.e. speed of recovery) (Benedikt et al., 2016; Morin et al., 2014).

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Nov 28, 2021 | Posted by in NURSING | Comments Off on 1: Introduction to Intervention Research
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