Social identities and the achievement gap: Incompatibility between social class background and student identity increases student disidentification, which decreases performance and leads to higher dropout rates.

Education is not equally distributed across all people. It has often been found that students from low social class background have lower access to universities, less academic achievement and higher dropout rates compared with their peers (called the 'achievement gap'). We investigate how the student social identity contributes to the emergence of the achievement gap and focus on student disidentification, a negative internalized relation to the in-group. We predict that disidentification reduces academic performance (Hypothesis 1) and increases university dropout rates (Hypothesis 2). Moreover, we predict that social class background affects identity incompatibility which, in turn, increases student disidentification (Hypothesis 3). We explore whether social class background affects long-term identity incompatibility, or whether identity incompatibility affects long-term disidentification by comparing two mediation models. Hypotheses 1 and 3 were supported cross-sectionally in a large sample (N = 2768), and longitudinally in a sub-sample 1.5 years later (N = 591). The data demonstrate that social class background has a long-term effect on incompatibility, which is related to disidentification. Hypothesis 2 was also supported in a (partly overlapping) sub-sample (N = 1077). The current research demonstrates that students with low social class background suffer from identity-related adaptation problems that affect their academic trajectories.