The choice of sample size

This paper discusses the problem of how large a sample to take from a population in order to make an inference about, or to take a decision concerning, some feature of the population. It first describes a fully Bayesian treatment. It then compares this with other methods described in recent papers in The Statistician. The major contrast lies in the use of a utility function in the Bayesian approach, whereas other methods use constraints, such as fixing an error probability.