To do so, researchers asked 315 U.S. ninth graders and 25 of their teachers to complete a series of questionnaires about their perceived similarity, as well as the quality of their relationship and their amount of interaction.
Participants were also given a “Get to know you” survey with such questions as: What is the most important quality in a friend? What foreign language do you speak, etc.
Half the students were then given feedback sheets informing them of 5 things they had in common with particular teachers. Likewise, the teachers were given similar feedback about half of their students.
Despite the simplicity of the intervention, the results were quite interesting. Not only did it make students and teachers feel more similar: its actually improved the quality and increased the quantity of their interactions, which resulted in higher average grades several months later.
What is more, the effect was concentrated on “undeserved” Black and Latino students, who received higher grades (by 40% of a letter grade) than their conterparts in the control group.
As the authors noted, 40% of a letter grade is the difference between a C+ and a B, and equal to ⅔ of the achievement gap between Whites / Asians and Blacks / Latinos (which amounts to 60% of a letter grade.)
Source: Gehlbach et alia (2016)