A personal view of some controversies in allocating treatment to patients in clinical trials

A non‐exhaustive but nevertheless wide‐ranging if biased and personal view of various matters affecting the allocation of treatments to patients in controlled clinical trials will be undertaken from the standpoint of a statistician working in drug development. The following topics are considered: the use of ‘placebos’ in the run‐in phase; the use of crossover trials; selection of patients; various matters concerning centres; two extreme alternatives to randomization, and various matters linking blinding and allocation.