Miller and Bizzell (1984) examined the long-term effect of Montessori preschool programs, as well as other preschool programs on the 9th- and 10th-grade performance of low-income African American students. No statistically significant differences on math and reading achievement scores (Comprehensive Tests of Basic Skills) were found between students who attended Montessori versus other preschool programs. Although the researchers noted higher performance for male students who attended Montessori programs, the higher scores paralleled student IQ scores. Such a finding does not allow achievement differences to be attributed to instructional programming (i.e., Montessori preschool).