In the medical field, accurate diagnosis of diseases is pivotal. The receiver operating characteristic (ROC) curve is a useful statistical graphic for evaluating laboratory test values in medical diagnosis. In recent years, some ROC curve methods and statistical inference methods based on the ROC curve have been proposed (e.g., Pepe, 1998: Wieand et al., 1989: Zou and Hall, 2000: Zweig and Campbell, 1993). However, few studies have identified the problem of the ROC curve regarding graphical representation. In this study, we consider this problem and develop three kinds of statistical graphics, namely, skill plot, likelihood ratio plot, and skillness plot. These plots were developed on the basis of power-normal distribution. The usefulness of these statistical graphics was evaluated using two practical examples. The results showed that our proposed graphics can overcome the problem of the ROC curve.