Researchers compared Montessori students with students in other school programs, and found that 5-year-old children who completed the three-year cycle in the Montessori preschool program scored higher on both academic and behavioral tests than the control group. The study also found that 12-year-old Montessori students wrote more sophisticated and creative stories and showed a more highly developed sense of community and social skills than students in other programs.
Read the research results in detail here in this attached pdf: