A student's achievement is partially influenced by a teacher other than his or her own, a recent study found.
When an effective teacher joins a grade-level teaching team, students' learning across the board improves as other teachers in the grade improve. Researchers from the University of Washington, Stanford University, and Vanderbilt University examined teacher "spillover" effects using over a decade of administrative data on math teachers in grades 3 to 8 and their students' standardized test scores in the Miami school district.
Novice teachers were excluded from the analysis, so the researchers could consider the effectiveness of both incumbent teachers (or those already in the school) and transfer teachers (or those who are new to the school, but had previously taught in the same grade level), based on their previous students' test scores.
The researchers found strong and consistent evidence of positive spillover effects: If a transfer teacher joins a grade-level team and is one standard deviation more effective than an incumbent teacher, the students in the incumbent teacher's class will see an increase in their math test scores, the data analysis found.