Comparison of tests on covariance structures of normal populations

In some studies, there is interest in testing the variance structure, as in the context of multivariate or modelling techniques. Therefore, the importance of using hypothesis tests on covariance structures is emphasized. The purpose of this study was to perform a detailed performance study regarding the power and type I error rate of some existing identity and sphericity tests, considering the scenarios with different numbers of variables (2 to 64) and sample sizes (5 to 100). The proposal of Ledoit and Wolf (2002) is the most appropriate to test the identity structure. For the sphericity test, the version of John (1972), modified by Ledoit and Wolf (2002), followed by the proposal of Box (1949), were the ones with the best performance.