ABSTRACT
Statistical significance deals with the question of whether a difference is reliable in light of random errors. Determining the statistical significance of a difference is the first step; determining the practical significance is the next step. Determining practical significance involves five considerations. The first consideration is the cost in relation to the benefit, which is often referred to as a cost-benefit analysis. In addition, a small, statistically significant difference can be of practical significance—even if it is costly—if it is a crucial difference (the second consideration). A crucial difference is one that results in an increase or decrease of great importance. The third consideration in determining practical significance is client acceptability. The fourth consideration is public and political acceptability. Fifth, the ethical and legal implications of statistically significant results should be considered. In addition, legal counsel may be needed to help in the determination of practical significance.
