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.
Retention of Participants
Retention of Participants
Obtaining a sample that is adequate in size and composition is important for maintaining the validity of inferences regarding the intervention effectiveness. However, the retention of the accrued sample is as critical for validity. Participants who complete all phases of the study (pre-test and post-test outcome assessment, exposure to treatment) should have the socio-cultural, health, and clinical profile comparable to that characterizing the target population. The number of participants remaining in the study should be large enough to detect significant intervention effects. In this chapter the role of participant retention in enhancing statistical conclusion, internal, and external validity is clarified. Factors associated with attrition are identified, and strategies for preventing and managing attrition, together with evidence of their effectiveness, are discussed.
Definition And Types Of Attrition
Attrition, also called mortality, dropout, or ...