Dropout often occurs in clinical trials with multiple visits.
Although the LOCF test has a long history of application, its statistical property is unknown prior to this study. In other cases, however, the asymptotic size of the LOCF test is different from the nominal size and is often too small, which results in a loss in power of detecting treatment effects, a disadvantage to drug companies. Some simulation results are presented to study the finite sample performance of the LOCF test and our proposed test for comparing global means.