Health Intervention Research

Understanding Research Design and Methods

Souraya Sidani, Author

• Publisher: SAGE Publications Ltd
• Year: 2014
• Print ISBN: 9781446256176, 9781446256169
• eBook ISBN: 9781473909243
• Edition: 1
• Topic: Social Sciences
• Subtopic: Social Science Research & Methodology
• Index: Social Sciences

At a time when evidence-based practice is the standard bearer for understanding health behaviour, problems and interventions, ensuring that researchers know the appropriate designs and methods for their research is more paramount than ever. Health Intervention Research will equip those doing research in these communities with the knowledge and tools they need to inform their methodological decisions when planning and conducting studies.

 

This book describes both commonly used (e.g., randomized clinical trials) and advanced (e.g. preference trials, pragmatic trials) designs and methods for health intervention research. It outlines the theoretical reasoning underlying these different approaches, and synthesizes the evidence which supports or disputes different designs and methods.

To achieve its aims, the book is divided into three main sections. The first section points to the need to base methodological decisions on evidence and highlights the importance of carefully selecting research designs and methods to maintain validity. The second section focuses on designs to determine the effects of intervention on outcomes, outlining their features and discussing how these can be used to evaluate interventions. The last section covers methods used in conducting intervention evaluation research. For each design and method, the following is covered:  what it is, what the logic underlying it is, what the evidence supporting its effectiveness is, and also includes its advantages, its limitations, and how can it be implemented.

 

This will be key reading for postgraduates and novice researchers in health and clinical psychology, health sciences and nursing.

1 An Overview of Health Intervention Research

Intervention forms a central element of healthcare in primary, acute, rehabilitation, and long-term care settings. Healthcare professionals assess clients’ condition to identify the problems requiring remediation, select and implement interventions to effectively address the problems, monitor clients’ responses to interventions, and evaluate their achievement of beneficial outcomes. Healthcare professionals include physicians, nurses, allied health therapists such as respiratory, physical, occupational and speech language therapists, psychologists, social workers, and health educators. They implement interventions, independently or collaboratively, that target problems manifested in different domains of health and experienced by individuals, families, groups (defined in terms of socio-cultural or clinical characteristics), or the entire community. The selection and implementation of interventions are informed by the best available evidence of their success in producing beneficial outcomes (Guyatt et al., 2002).

Research is widely recognized as a source of evidence because of its systematic process aimed at making valid inferences about the causal effect of the intervention on outcomes. Research is guided by a comprehensive understanding of the intervention, and of the notions of causality and validity. In this chapter, the logic of intervention research is described relative to the notion of causality. It rests on a lucid knowledge of the intervention and its contribution to the hypothesized outcomes, as delineated next. Validity is discussed in Chapter 2.

Health Intervention Research

Health intervention research involves the systematic evaluation of the merit, worth, or value of interventions. The value of interventions is indicated by the extent to which the interventions are appropriate, safe, and effective in managing clients’ problems and in improving their health. The goal of health intervention research is to demonstrate the causal relationship between interventions and anticipated outcomes. The causal relationship implies that the interventions, and no other contextual factors, are responsible for inducing the beneficial changes in outcomes. Evaluation of the interventions’ effects on outcomes requires an understanding of the problem that the intervention targets, the intervention, the outcomes, the mediators or mechanisms through which the intervention exerts its effects on the outcomes, and the moderators or factors that influence the intervention effects.

Problem

Problems are alterations in clients’ health condition that put them at risk for illness or that interfere with their engagement in healthy behaviors and activities of daily living. The alterations include: bio-physiological malfunctions such as high blood sugar and hypertension; physical limitations such as difficulty walking; cognitive impairment such as delirium; emotional symptoms such as anxiety; engagement in risky behaviors such as smoking; and social issues such as isolation. An understanding of the problem clarifies its nature, manifestations, determinants, and level of severity. Nature of the problem refers to the domain of health in which it is experienced. Manifestations are the indicators (i.e., signs and symptoms) that point to the occurrence of the problem. Determinants are causative factors that contribute to the experience of the problem. Level of severity reflects the intensity with which the problem is experienced. This understanding of the problem is necessary for determining the appropriateness of the intervention and for guiding the design of the intervention evaluation study.

Interventions are considered appropriate when they are reasonable and logical in that they specifically address the problem requiring remediation (hereafter referred to as health problem). The nature of the intervention fits with the nature of the health problem. Awareness of the nature, determinants, and manifestations assists in identifying the aspects of the health problem that are amenable to change and hence, targeted by the intervention. Also, it is instrumental in delineating intervention strategies that are consistent with the modifiable aspects of the health problem and, hence, relevant in addressing or resolving it (Lippke and Ziegelman, 2008; Slater, 2006). Knowledge of the level of severity with which the health problem is experienced helps in specifying the dose at which the intervention is given to induce the desired changes in the problem experience (Sidani and Braden, 2011). Congruence between the health problem and the intervention enhances the specificity of the intervention. The intervention targets what exactly and significantly contributes to the health problem; it does not address its ‘wrong’ aspect and therefore, miss the target (Green, 2000; Nock, 2007). The specificity of an intervention increases its effectiveness.

A thorough understanding of the health problem informs the identification of the client population and the sample selection criteria for the intervention evaluation study. The population is generally defined relative to the experience of the problem targeted by the intervention. The sample selection criteria are specified to ensure that persons report the particular aspects of the problem specifically addressed by the intervention. These persons are expected to benefit most from the intervention.

Intervention

Health interventions are treatments, therapies, procedures, or actions that are implemented by healthcare professionals to, with, or on behalf of clients, in response to the health problem with which clients present, to improve their condition and achieve beneficial outcomes. Interventions consist of a set of interrelated activities that healthcare professionals perform; the activities reflect the cognitive, verbal, and physical functions within the scope of the professionals’ practice. Health interventions include bio-physical treatments such as medications or administration of intravenous fluids; physical procedures such as surgical removal of a cyst and therapeutic massage; psychological, cognitive, behavioral, motivational, and educational interventions to promote engagement in healthy lifestyle; and social actions such as facilitating social gathering of older adults residing in long-term care institutions.

Understanding of an intervention taps into its goals, specific and non-specific elements, mode of delivery, and dose. An intervention’s goal refers to its overall direction, that is, what the intervention is set to achieve relative to the targeted health problem, such as prevention, management, or resolution of the problem, and to the clients’ general condition such as improved functioning. The specific elements are the active ingredients that characterize an intervention and distinguish it from others. The active ingredients are theoretically expected to induce changes in the health problem and clients’ general health condition. The non-specific elements are strategies or activities that facilitate the implementation of the active ingredients but are not anticipated to contribute to changes in the health problem and the clients’ condition (Hart, 2009; Stein et al., 2007). For instance, stimulus control therapy is a behavioral intervention for the management of chronic insomnia. Its primary goal is to assist persons to re-associate the bed and the bedroom with sleep. Its active ingredients consist of instructions regarding activities to avoid (such as reading or thinking) and activities to do (such as getting out of bed if one can’t fall asleep) around bedtime. Its non-specific elements include monitoring the application of the instructions for feedback and discussing barriers to the implementation of the instructions. Mode of delivery reflects the medium, format, and approach for offering the intervention. Medium is the means through which the intervention is given, which can be oral (e.g., facilitation of group discussion on barriers to healthy behavior performance), written (e.g., distribution of pamphlet), and hands-on (e.g., surgery, massage). Format is the specific technique used for providing the intervention. Different formats are available such as face-to-face meetings or videotaped presentations within the oral medium, and booklet and computer-based application within the written medium. Approach is the structure selected for providing the intervention, which can be standardized or tailored. In a standardized approach, the same intervention is carried out in the same way, at the same dose, across all clients. In contrast, a tailored approach consists of customizing the intervention, its mode of delivery, and its dose, to be responsive to clients’ characteristics, needs, and preferences. Dose is defined as the level at which the intervention is to be given in order to successfully achieve the preset goals. It is operationalized in terms of amount (i.e., number of sessions, length of each), frequency (i.e., number of times the sessions are given within a specified period of time), and duration (i.e., total time period for giving all sessions).

Knowledge of the intervention’s goals, active ingredients, non-specific elements, mode of delivery, and dose gives direction for the operationalization of the intervention. This, in turn, facilitates its implementation with fidelity and monitoring its delivery. Implementation of the intervention with fidelity in an intervention evaluation study is critical for initiating the mechanisms responsible for producing the outcomes (Borrelli et al., 2005).

Operationalization of the intervention consists of translating the knowledge of the intervention’s goals, active ingredients, and non-specific elements into components and activities that are performed within the selected mode of delivery and dose, by the healthcare professionals responsible for delivering the intervention (hereafter referred to as interventionists) and by clients receiving the intervention. A component is a set of interconnected activities that address one modifiable aspect of the health problem or that target a particular domain of clients’ general condition. The number of components determines the level of intervention complexity. Simple interventions comprise a single component, for example, acupressure for the management of nausea and vomiting, or education for enhancing clients’ knowledge of factors that trigger dyspnea. Complex interventions involve multiple components. The components may address different aspects of the health problem or domains of clients’ general conditions. For example, a diabetes self-management program would include a component aimed at increasing clients’ engagement in physical activity and a component aimed at promoting a low carbohydrate diet. The components may also represent different strategies to manage the same problem; the strategies may target individuals (e.g., cognitive and behavioral strategies to improve adoption of health behaviors), or several constituents in a community (e.g., behavioral strategies for individuals, organization of support groups, and involvement of the community in maintaining safe neighborhoods, to increase participation in physical activity). A list of specific activities is generated to operationalize each component and integrated into a meaningful sequence of activities to be carried out, in the specified mode, within and across all intervention contacts or sessions. A detailed description of these specific activities is compiled in the intervention protocol, which is detailed in a manual.

The nature of the intervention’s specific activities point to the professional qualifications and personal characteristics required of the interventionists. The interventionists should have the professional qualifications (e.g., formal training, licensing) that enable them to carry out the intervention activities, as determined by respective regulatory bodies. Some personal characteristics (e.g., gender, ethnicity) may be important to facilitate delivery of some interventions such as those addressing sensitive topics to some client populations. For example, women are more comfortable discussing sexuality issues with female interventionists.

The intervention protocol is foundational for training interventionists in the competencies required for an appropriate implementation of the intervention (Borrelli et al., 2005). The competencies relate to the conceptual underpinning of the intervention and the practical skills for carrying out its activities. Through intensive training, interventionists should gain an understanding of the health problem targeted by the intervention; the intervention’s goals, active ingredients, non-specific elements, mode of delivery, and dose; and the mechanisms responsible for producing its effects on the outcomes. The interventionists also should be familiar with the intervention protocol, the rationale for each specific activity, the standards for carrying out the activities, potential challenges in carrying out the activities and ways to manage them (Sidani and Braden, 2011).

The intervention protocol serves as the reference for implementing the intervention and for developing instruments to monitor fidelity of intervention implementation. Interventionists are requested to follow the protocol when delivering the intervention. The activities to be performed are incorporated in an instrument for assessing the fidelity of implementation (Stein et al., 2007). Fidelity refers to the consistency between the actual delivery and the original design of the intervention; that is, the specific activities constituting the intervention are carried out as specified in the protocol. Deviations in the implementation of the intervention from its original design and across clients result in inconsistency in the intervention activities to which clients are exposed. This inconsistency contributes to variation in the level of outcome improvement reported by clients following implementation of the intervention, which reduces the power to detect significant intervention effects (Carroll et al., 2007; Leventhal and Friedman, 2004).

Furthermore, knowledge of the intervention’s active ingredients, non-specific elements, and dose is necessary for:

1. Selecting the comparison treatment that serves as a control condition for determining the effects of the intervention on outcomes. The comparison treatment should not contain components or activities that may reflect the intervention’s active ingredients in order to maintain a clear distinction between the two treatments and maximize the difference in the outcomes.
2. Identifying the most appropriate time, within the trajectory of the health problem, to provide the intervention such as before, during, or following its experience.
3. Determining the most accurate methods for collecting data on the intervention dose to which clients are exposed and for conducting dose-response analyses, which is important in specifying the optimal dose associated with beneficial outcomes.

Outcomes

Outcomes represent the consequences of the intervention. They capture the changes in a clients’ condition expected to take place following receipt of the intervention and reflect the criteria for determining its benefits. Outcomes are derived from the goals of the intervention and classified into immediate and ultimate outcomes. Immediate outcomes entail the expected changes in the aspects of the health problem that are directly targeted by the intervention, and occur within a short time interval after the implementation of the intervention. Immediate outcomes are operationalized as modifications in the health problem’s determinants, manifestations, or level of severity. Ultimate outcomes include resolution of the problem and improvement in other aspects of clients’ general condition such as prevention of illness and promotion of healthy functioning. Achievement of ultimate outcomes follows changes in the immediate outcomes. Therefore, the immediate outcomes mediate the effects of the intervention on the ultimate outcomes. For example, stimulus control therapy is designed to assist persons with insomnia to re-associate the bed and the bedroom with sleep. Application of its instructions is expected to reduce the time it takes to fall asleep and the time awake after sleep onset, which yields an increase in sleep efficiency (immediate outcomes). Increased sleep efficiency is associated with the perception of low levels of insomnia severity (resolution of the problem), which decreases daytime fatigue and improves physical, psychological, and social functioning (ultimate outcomes).

Understanding the nature, classification, and interrelationships among outcomes has implications for outcome assessment and analysis in the intervention evaluation study. Awareness of the outcomes’ nature directs their operationalization. Each outcome should be clearly defined at the conceptual level; its domains and dimensions that are expected to demonstrate changes post-intervention delivery (i.e., post-test) are identified, as they will guide the selection of the instrument to measure the outcome. A correspondence between the outcome domains and dimensions as defined conceptually and as captured in the content of the instrument is required to accurately assess the outcome and quantify the changes in the outcome. For example, the cognitive, more so than the physical, domain and the intensity, more so than frequency, dimension of daytime fatigue are expected to improve after delivery of the stimulus control therapy.

Classification of outcomes into immediate and ultimate informs the specification of the anticipated pattern of change in the outcomes. Usually, significant ...

Table of contents

• Cover
• Half Title
• Publisher Note
• Title Page
• Copyright Page
• Contents
• About the Author
• Preface
• Acknowledgments
• 1 An Overview of Health Intervention Research
• 2 Validity in Intervention Research
• 3 Phases of Intervention Evaluation Research
• 4 Experimental Designs or Randomized Controlled Trials: Characteristic Features
• 5 Experimental Designs or Randomized Controlled Trials: Limitations
• 6 Advances in Intervention Evaluation Designs: Extensions of Experimental Designs
• 7 Advances in Intervention Evaluation Designs: Pragmatic and Preference Trials
• 8 Selection of Participants
• 9 Retention of Participants
• 10 Assignment of Participants to Study Groups
• 11 Implementation of the Intervention
• 12 Principles of Outcome Measurement and Analysis
• References
• Index