[Researching identity development and statuses with the Dimensions of Identity Development Scale: the Japanese version].

The Dimensions of Identity Development Scale (DIDS) provides a new method of researching identity development based on the dual-process model pertaining to lifespan development. This study developed and evaluated the Japanese version of this scale (DIDS-J). Two surveys of undergraduate and high school students showed that the DIDS-J had good reliability and validity and that it consisted of 25 items with five factors: commitment making, identity with commitment, exploration in breadth, exploration in depth, and ruminative exploration. Through cluster analysis of the DIDS-J, five identity statuses were found that were not clearly distinguished by previous scales: foreclosure, achievement, searching moratorium, diffused diffusion, and carefree diffusion. Research using the DIDS-J has two advantages: it enables us to examine the process of identity development among adolescents with a wider age range, and to compare results cross-culturally in future research. The trial investigations compared student scores with those from previous research in Western cultures, demonstrating that DIDS-J may lead to further explanations of identity development.