ABSTRACT
In Chapter 1, we looked at some common types of observational study designs. In this chapter, we examine randomised controlled trials (RCTs), a study design whereby the investigator intervenes (most commonly by introducing a new drug) and observes the effect of the intervention through measuring some outcome measures. The key advantage of an RCT over observational study design lies in the fact that it is usually easier to establish causality and confounding can be minimised. Drug trials usually employ RCTs, as they provide the highest level of evidence among all the epidemiological study designs. The various types of RCTs and key features such as randomisation and use of controls will be highlighted in this chapter. Newer trial designs, including the stepped wedge RCT, are introduced, along with a section on the role of a statistician in a Data and Safety Monitoring Board of an RCT. A unique feature of this chapter relates to the provision of issues and concerns to discuss and clarify with collaborators during the design phase of an RCT. Another important section of this chapter relates to the choice of outcome measures in an RCT and the critical role the biostatistician should play in the identification and selection of the outcomes. A real-life collaborative case study is provided at the end of the chapter.
