Dimensions of Identity Development Scale (DIDS): A test of longitudinal measurement invariance in Greek adolescents

Identity is one core developmental task of adolescence. Although Marcia’s model, comprising of the dimensions of exploration and commitment, has dominated identity research for decades new models have recently been proposed. Luyckx and colleagues’ model poses that identity is a process consisting of five aspects: Exploration in Breadth, Commitment Making, Ruminative Exploration, Exploration in Depth and Identification with Commitments. The Dimensions of Identity Development Scale (DIDS) is a 25-item instrument developed to assess those five aspects. The goal of this study is: (a) to test the applicability of DIDS in a sample of Greek adolescents, and (b) to investigate the longitudinal measurement invariance of the scale. The results support the use of DIDS in Greek context and show that strong measurement invariance holds longitudinally in the course of 12 months. Echoing recent studies, the six-factor model showed significantly better fit, with Exploration in Depth splitting to Exploration in Depth and Reconsideration of Commitment. The scale is suitable for studies of longitudinal change in identity development.