A method for measuring performed by a user equipment (UE) in a wireless communication system is provided. The method includes: camping on a serving cell operating on a serving frequency; receiving a reselection priority information, the reselection priority information indicating signaled priorities for the serving frequency and a inter-frequency; determining whether to apply an implicit highest priority to the serving frequency for measurement; and measuring the inter-frequency based on the signaled priorities. The step of the determining comprises: wherein if the UE receives a logged measurement configuration for a logged Minimization Driving Test (MDT) and a type of the serving cell is a predetermined type, determining to apply a signaled priority for the serving frequency indicated by the reselection priority indication.