As have mentioned in previous papers(Tauxe and Kent, 2004; Tauxe, 2005; Tauxe et al., 2008), the E/I method depends on several key assumptions and one of them is that sufficient measurements of the ancient geomagnetic field are needed. Many researchers believe that the E/I method needs to average out the paleosecular variation ( Kodama, Tan and etc.). But I still suspect what happen if the E/I method is performed on a data set that has not average out the paleosecular variation.