Methodological Foundations of Clinical Research

Abstract

This chapter focuses on clinical experiments, discussing the phases of the pharmaceutical development process. We review the conceptual framework and classification of biomedical studies, and look at their distinctive characteristics. Biomedical studies are classified into two main categories: observational and experimental, which are then further classified into subcategories of prospective and retrospective, and community and clinical, respectively. We review the basic concepts of experimental design, including defining study samples and calculating sample size, where the sample is the group of subjects on which the study is performed. Choosing a sample involves both qualitative and quantitative considerations, and the sample must be representative of the population under study. We then discuss treatments, including those that are the object of the experiment (study treatments) and those that are not (concomitant treatments). Minimizing bias through the use of randomization, binding, and a priori definition of the statistical analysis is also discussed. Finally, we look at how adaptive clinical trials can shorten the time and reduce the cost of classical research programs. Such adaptation strategies are relatively new in clinical research and allow for modification of the sample size, adjusting study duration, and other changes.