An alternative method for sample size determination in substance misuse prevention research

There is considerable evidence that social science researchers often fail to adequately address statistical power and related sample size issues. This tendency has been particularly salient in substance misuse prevention research. Although failure to carefully address statistical power and sample size issues most frequently results in studies lacking statistical power, other problems can also occur. For example, sample size determination in controlled studies which focus on rates of substance initiation and similar measures require close consideration of baseline rates indicated by these measures. Otherwise, when conventional procedures for sample size determination are utilized, samples in these studies can exceed the size necessary for predesignated levels of power. This article presents a simple alternative to conventional procedures for sample size determination which can be applied to controlled study of substance initiation and similar outcomes.