Making classrooms more inclusive reduces the achievement gap in STEM: evidence from a large-scale randomized controlled trial

Students from marginalized groups tend to achieve lower grades in STEM college courses than their non-marginalized peers. We tested the effectiveness of two interventions, one aimed at changing the environment and the other aimed at changing the students. The “Inclusion intervention” helped instructors create a cooperative classroom environment where students felt interconnected and pro-inclusion social expectations were made explicit. The “Resilience intervention” consisted of well-established strategies that focus on changing the cognitions and attributions of students from marginalized groups. We compared the two interventions against a no-exposure control group in a large-scale cluster-randomized controlled trial involving 60 STEM courses ( N Students = 2,116). Results show that in courses assigned to the Inclusion intervention, students from marginalized racial/ethnic groups obtained better grades – more than half a letter grade – than those in the control condition, whereas the Resilience intervention had little beneficial effect. Our research demonstrates the importance of making the classroom environment more inclusive.