Bradford Hill has defined a clinical trial as "A carefully and ethically designed experiment with the aim of answering some precisely framed question" 1]. This definition specifies a careful design and requires the provision of adequate controls. Random allocation of treatments to subjects is important to ensure is entitled that the treated and control groups are similar. Therefore this book Randomised Controlled Clinical Trials. We can define a randomised controlled trial by rewriting Bradford Hill's definition as follows, "A carefully and ethi- cally designed experiment which includes the...