Abstract
Many researches claim that self-evaluation data by Cds items is considered as a scale with high validity. However, it is also reported that many learners quite often evaluate their acquisition levels lower than before. This paper aims to show that this "Lowering" observed in self-evaluation data by Cds items is considered to co-occur with learners' progress in understanding their acquisition levels and therefore it can possibly be used as a tool to estimate learners' language proficiency level.
