The document summarizes a study conducted with 26 schools that assessed the impact of trainee teachers on student achievement and attitudes. Key findings include: 1) Student attitudes were mostly positive both before and after a 6-week placement period with trainee teachers, with only a modest negative shift in mathematics. 2) Overall, student achievement increased after exposure to trainee teachers, with average scores rising by 0.27 points for all students, 0.25 for boys and 0.30 for girls. 3) Mentor teachers generally provided positive feedback on trainee teachers and commented that their involvement allowed for new teaching strategies, better understanding of students, and more individualized learning.