Seeking to ensure that every classroom is led by a qualified teacher and every student makes up lost learning ground from the pandemic, many school leaders are focusing on recruiting or retaining teachers, or bringing in additional support like intensive tutoring. However, a new study suggests an opportunity to better leverage current teachers: match them with students they've taught before.

A new Annenberg Institute at Brown University working paper by Leigh Wedenoja, John Papay, and Matthew Kraft employs data from Tennessee to find that having a teacher for multiple years (not necessarily multiple years in a row) is related to better student academic and behavioral outcomes.

For the most part, the matches identified in the analysis are not intentional "repeat matches," like in a looping system where a teacher and students all move up a grade together. Rather, the study looks at repeat matches that occur by happenstance, such as when an elementary teacher moves up a grade and has some of her same students again, or when a high school teacher teaches multiple science courses and so sees the same students in different years.

The study found that when students are assigned to a teacher for the second time, they tend to have some sizable ELA and math gains (about 2% of a standard deviation), with slightly bigger gains in high school. But when the researchers dig into the data by student demographics, they find that higher-performing students (in the top-half of the test score distribution) experience the greatest academic gains, as do white female students. Female students of color do not appear to benefit at all from having repeat teachers; all male students see some gains, but less than white female students.

Students with repeat teachers also see behavioral gains: fewer absences, fewer suspensions, and less truancy (at the high school level). The size of these effects were generally modest (for example, absences for students with the same teachers were only half a percent lower), but meaningful; the authors note that even one instance of 9th grade truancy predicts a lower likelihood of graduating high school. Unlike the academic achievement results, which were greatest for higher-achieving students and white female students, the behavioral improvements were greatest for students in the lower half of the academic distribution and for male students of color.

There is much for school leaders to ponder in this work. Changes to teachers' grade and subject assignment should not be made lightly: most past research finds that teachers are less effective when they switch grades, at least temporarily. However, if these teachers can work with the same group of students in an intentional manner, the gains from any prior relationship that the students and teacher have built may offset the risk. Schools may be able to operationalize this research, building into their class-scheduling process a check for whether students have been taught by a teacher before or not (ideally with confirmation that the relationship between the student and teacher was generally a positive one). Leaders should also keep an eye on equity, to avoid a situation where students who are furthest from opportunity are repeatedly assigned to less effective teachers.