“…The studies mentioned above, however, so far ignored the question whether, beyond individual characteristics, classroom characteristics (e.g., sociocultural composition, cognitive ability of peers) might also affect student outcomes in inclusive educational settings. As known from school effectiveness research, aggregate-level characteristics might moderate the effects of student-level characteristics on individual outcomes (e.g., Müller & Zurbriggen, 2016). Overall, most of these studies (e.g., Hattie, 2002;Van Ewijk & Sleegers, 2010) showed that characteristics of the composition of the learning environment can increase the effect of disadvantaging individual characteristics on outcomes.…”