Source: Stuck in the Middle, Fall 2010
(the source is worth reading in its entirety)
What we found bolsters the case for middle-school reform: in the specific year when students move to a middle school (or to a junior high), their academic achievement, as measured by standardized tests, falls substantially in both math and English relative to that of their counterparts who continue to attend a K–8 elementary school. What’s more, their achievement continues to decline throughout middle school. This negative effect persists at least through 8th grade, the highest grade for which we could obtain test scores.
Moreover, these are not temporary dips followed by rebounds in learning. Throughout the middle-school years, students fall further behind. After two years in a middle school, on average a student who entered in the 7th grade will score 0.10 standard deviations in math and 0.09 standard deviations in English below what we would expect if he had gone to a K–8 school.
After three years in a middle school, a student who entered in the 6th grade will underperform on 8th-grade assessments by 0.17 standard deviations in math and by 0.14 standard deviations in English.
At least part of the problem with middle schools may be that they usually combine students from multiple elementary schools. In the New York City schools we studied, the average cohort size was 75 students in K–8 schools, 100 students in K–5 and K–6 schools, and over 200 students in middle schools for grades 6–8 and 7–8 (see Figure 3). We went back to our data and analyzed the effect of these cohort size differences on test scores. What we found was that cohort size has a pronounced influence on student achievement during these school years.
The clearest pattern that emerges from student reports is that 6th and 7th graders in middle schools think their schools have less academic rigor, less mature social behavior among the students, are less safe, and provide lower-quality education than do 6th graders in K–6 or K–8 schools.
Southwest MS has 1305 students for grades 6-8 (see source here). Thus the average number of students for each grade (or cohort) is approximately 430 students. Sand Lake ES has about 490 students for grades K-5. Thus the average number of students for each grade is approximately 81.
Advancing from Sand Lake ES to Southwest MS results in a cohort that is about 5X larger. For the NYC study, the cohort growth from K-5 (or K-6) schools to middle schools was only 2X.