Issues in Randomization Outline

What do we mean by random?• Everyday speech– Process is random if there is no discernablepattern• Statistics– Random characterizes a process ofselection that is governed by a knownprobability rule for example 2 treatmentshave equal chance of being assigned– Random in statistics does not meanhaphazard4What is random treatmentallocation?“By random allocation, we mean that eachpatient has a known chance, usually equalchance, of being given each treatment, butthe treatment to be given cannot bepredicted.” (Altman 1991)5What is random treatmentallocation?• Randomization is the act of allocating arandom treatment assignment• A patient is said to be randomized to atreatment arm or group when they areassigned to the treatment group usingrandom allocation• Clinical trials that use random treatmentallocation are referred to as randomizedclinical trials62