Perspectives on Statistical Significance Testing

The question of whether statistical significance testing should be used for the analysis of public health and epidemiologic data has received considerable attention in recent years. In this paper we have described some of the arguments for and against the use of hypothesis testing for the analysis of biomedical data. In addition, we have reviewed the literature from related fields, in particular sociology and psychology, in which similar discussions have taken place within the last 30 years. Many of the significance testing criticisms in these scientific fields have been raised in the more recent discussions taking place in the biomedical field. We present an example that emphasizes the use of both confidence interval estimation and significance testing. The example is particularly pertinent because it represents a more complex problem than has generally been discussed by critics of significance testing. Much of the discussion on this topic has focused on simple data analysis, such as the analysis of a 2 x 2 table or problems involving simple linear regression. Most epidemiologic data are far more complicated and warrant the use of both confidence interval estimation and significance testing for statistical analysis. Both of these techniques have no doubt been misused in the analysis of data. These misuses may have arisen from a lack of understanding of the role of statistical methods in data analysis and the choice of such methods for data analysis. If used prudently and judiciously, significance testing can help reduce the number of variables involved in a statistical analysis, thereby resulting in shorter confidence intervals for the models presented. Both significance testing and confidence interval estimation can serve and have served very useful functions for the analysis of public health and biomedical data.