Basic principles of study design

At the end of Chapter 3 we noted that we would provide operational definitions of the terms good and appropriate study design in the context of answering an important research question of biological (clinical) importance. Two more quotes from Piantadosi (2005) and ICH Guidance E8 (1997) are illuminating  

Conceptual simplicity in design and analysis is a very important feature of good trials. Good trials are usually simple to analyze correctly. 

Clinical trials should be designed, conducted, and analyzed according to sound scientific principles to achieve their objectives. 

Our operational definition of the term appropriate in the context of the design of clinical 

Clinical trials embody several fundamental principles of experimental design (Piantadosi, 2005). Three of these are  

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