Middle school. The very words are enough to make many Americans
shudder with memories of social anxiety, peer pressure, bad haircuts,
and acne. But could middle schools also be bad for student learning?
Could something as simple as changing the grade configuration of schools
improve academic outcomes? That's what some educators have come to
believe.
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States and school districts across the country are reevaluating the
practice of educating young adolescents in stand-alone middle schools,
which typically span grades 6 through 8 or 5 through 8, rather than
keeping them in K-8 schools. The middle-school model began to be widely
adopted almost 40 years ago. Now, reformers in Massachusetts,
Pennsylvania, Ohio, Tennessee, Oklahoma, Maryland, and New York, and the
large urban districts of Cincinnati, Cleveland, Philadelphia, and
Baltimore, are challenging the notion that grouping students in the
middle grades in their own school buildings is the right approach.
Why the turn against middle schools? For more than three decades,
American public education embraced this organizational model. Between
1970 and 2000, the number of public middle schools in the U.S. grew more
than sevenfold, from just over 1,500 to 11,500. These new middle schools
displaced both traditional K-8 primary schools and junior high schools
(which first appeared a century ago and served grades 7-8 or 7-9). From
1987 to 2007, the percentage of public-school 6th graders in K-6 schools
fell from roughly 45 percent to 20 percent.
Neither the middle school nor the junior high has ever been popular
among private schools, which educated only 2 percent of their 6th and
7th graders in these types of schools in 2007. And maybe the private
schools have had it right all along. For the last two decades, education
researchers and developmental psychologists have been documenting
changes in attitudes and motivation as children enter adolescence,
changes that some hypothesize are exacerbated by middle-school curricula
and practices.
These findings are cause for concern, but there is reason to doubt
their conclusions. Because the studies use data from a single school
year to contrast students in middle schools and K-8 schools, most of the
available research cannot reject the possibility that differences
between the groups of students, rather than in the grade configuration
of their schools, are actually responsible for the differences in
behavior and achievement.
To provide more rigorous evidence on the effect of middle schools
on student achievement, we turned to a richly detailed administrative
dataset from New York City that allowed us to follow students from grade
3 through grade 8. Some of these children attended middle schools and
some did not. Because we could follow the same children over a period of
time, we could do a better job of ruling out the role of influences
other than middle-school attendance on educational outcomes.
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.
We found that the middle-school achievement gap cannot be explained
by a scarcity of financial resources for the schools. Instead, the cause
is more likely to be related to other school characteristics, especially
the fact that middle schools in New York City educate far more students
in each grade. Although our conclusions about the reasons for the
middle-school gap are tentative, we are quite confident that the
evidence shows that middle schools are not the best way to educate
students--at least in places like New York City.
Data and Methods
Our study was based on data for New York City school children who
were in grades 3 though 8 during the 1998-99 through 2007-08 school
years. We were able to follow students who entered 3rd grade between the
fall of 1998 and the fall of 2002 for six years, until most had
completed the 8th grade. We have data about the grade configuration and
other characteristics of their schools, individual academic achievement
as measured by annual standardized test scores in math and English, and
a variety of personal characteristics. In particular, we know each
student's gender, ethnicity, whether they received free or
reduced-price lunch through the federal lunch program, whether they were
English language learners or received special education services, and
their record of suspensions and absences from school.
Elementary schools in New York City typically serve students until
grade 5 or grade 6, while a smaller portion of elementary schools run
through grade 8. This means that most students move to a middle school
in either grade 6 or grade 7, while some never move to a middle school.
Of the 3rd graders in our initial sample of students, 62 percent were in
a K-5 school, 24 percent were in a K-6 school, and 7 percent were
enrolled in a K-8 school. The small fraction of remaining students
attended K-3, K-4, or K-7 schools and are excluded from our analysis.
To isolate the impact of attending a middle school from the many
other factors that influence student achievement, we combined two basic
strategies. Most importantly, we tracked the performance of individual
students over time to see how their performance evolved relative to that
of their peers as they progressed from grades 3 to 8, in essence, using
each student as his or her own control group. This step alone provides
much stronger grounds for conclusions about the effects of attending a
middle school than previous research.
A lingering concern, however, is the possibility that different
types of students choose to attend middle schools than choose to
continue in a K-8 school. If students do sort themselves into middle
schools because of some unobserved characteristic that causes changes in
academic achievement over time, we would incorrectly attribute
differences in achievement to the middle schools instead of to
characteristics of the students themselves. We reduced the likelihood of
making this mistake by using a statistical technique that effectively
takes the choice to switch schools out of the students' (or
parents') hands. Specifically, we ran a statistical model that used
the last grade served by the school that a student attended in grade 3
to predict whether the student attended a middle school. We then used
that prediction to place each student into one of the two groups we are
comparing, that is, students who attend middle schools and those who do
not. Our key assumption in taking this approach is that there are no
unobservable factors that cause a drop in student achievement at
precisely the same time as students must leave the elementary schools
they attended in grade 3. While we cannot definitively rule out the
existence of such factors, we do not know of any plausible alternatives
that, would explain our findings.
The Middle-School Disadvantage
What determines a student's level of academic achievement is
complex. But the simple fact is that students who enter public middle
schools in New York City fall behind their peers in K-8 schools. This is
true both for math and English achievement. Even more troubling, the
middle-school disadvantage grows larger over the course of the
middle-school years. With the transition into a middle school, students
set out on a trajectory of lower achievement gains.
The achievement gap between middle-school students and K-8 students
is put in stark relief in Figure 1, which displays our estimates of the
impact of attending a middle school on student achievement as measured
by standardized tests in math and English Language Arts. The graphs show
how well students who attend a middle school perform relative to how we
would expect them to perform if they attended a K-8 school. We report
those differences, in standard deviations of student achievement in math
and reading, for the 3rd through 8th grades. We separate students who
enter a middle school in grade 6 from those students who enter a year
later, in grade 7.
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No matter whether students enter a middle school in the 6th or the
7th grade, middle-school students experience, on average, a large
initial drop in their test scores. Even after accounting for a host of
other factors that influence student achievement, students who
eventually attend middle schools go from scoring better than their
counterparts in K-8 schools in the year prior to transitioning to middle
school to scoring below where we would expect if they were not attending
a middle school. Math achievement for 6th graders transitioning to
middle school falls by 0.18 standard deviations, and English achievement
falls by 0.16 standard deviations. Contrast that decline with the
6th-grade test scores for students who will enter middle school the
following year, in the 7th grade. Their test scores in both subjects
continue to improve relative to their peers in K-8 schools. When these
6th graders move to a middle school in the 7th grade, however, we see
the same dramatic fall in academic achievement: math scores decline by
0.17 standard deviations and English achievement falls by 0.14 standard
deviations. Just how large are these effects? Consider that decrease in
achievement associated with middle school entry--between 0.14 and 0.18
standard deviations--is roughly 20 to 25 percent of the achievement gap
between poor and non-poor students (as measured by free lunch receipt)
in New York City (about 0.7 standard deviations).
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.
A particularly distressing finding from our study is that students
with lower initial levels of academic achievement fare especially poorly
in middle school. To investigate the possibility of different effects on
students with higher and lower initial achievement levels, we separated
students into two groups: one group had grade 3 test scores above the
citywide median, the other group scored below the median. Although we
found substantial drops in achievement during middle school for both
groups of students, the first-year drop and cumulative deficit were,
respectively, 50 percent and more than 200 percent greater for students
who start at the lower end of the achievement distribution.
We also found evidence that student absence rates increased when
students entered middle schools and were significantly higher in grade 8
than for students who never entered a middle school (see Figure 2). More
specifically, our estimates indicate that students were missing almost
two additional days of school per year than would have been the case had
they attended a K-8 school. Thus, increased absences may be one
mechanism through which middle schools lower student achievement. There
is little chance, however, that absences could explain a large share of
the overall effect of attending a middle school.
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To be sure, the population of public school children in New York
City is different from that of many other school districts around the
country. These differences might mean that middle-school attendance
would have smaller or larger effects on other students than we estimate
it to have on New York City's public school children. For example,
students with fewer educational resources at home maybe more strongly
affected by changes in their school environment. If that is the case,
studying New York City students, who arguably come from less advantaged
backgrounds than, say, the students in New York City suburbs, may have
led us to find a larger middle-school effect than had we followed a
more-affluent student population. While we encourage readers to be
cautious about applying our findings without qualification to all public
schools, we also encourage school districts to support research that can
identify middle-school effects in other settings, especially since we
find the consequences of attending a middle school for student
achievement to be substantial and troubling.
Explaining the Trouble with Middle Schools Why might New York
City's middle schools be detrimental to academic achievement? We
find little support for the notion that differences in resources, such
as per-pupil expenditures and class size, could explain the
middle-school achievement gap. In middle schools serving grades 6-8 and
grades 7-8, average per-pupil expenditures were $10,094 and $11,082,
respectively, while per-pupil expenditures in K-8 schools were roughly
equivalent, at S 10,950. Nor do students experience a large decline in
per-pupil spending when they move to a middle school. Average per-pupil
expenditure in K-5 schools was $10,144 (compared to the $10,094 for
grade 6-8 middle schools) and 59,680 in K-6 schools (compared to $11,082
in grade 7-8 middle schools).
Nor can we attribute the disparity we see to differences in class
size. The average class size is slightly smaller for 5th graders in K-5
schools than for 6th graders in 6-8 schools (24 vs. 25 students);
students in K-8 schools see similar growth in class size between grades
5 and 6. Class size is actually larger for grade 6 students in K-6
schools than for grade 7 students in 7-8 schools (24 vs. 23 students).
What about the possibility that the relative age of students in a
school, especially during adolescence, can influence how students learn?
In other words, does being the youngest students in a school have
negative effects on the educational experience of those students? We
could not find evidence in our data to support this explanation for the
initial drop in test scores upon transitioning to a middle school. In
our study sample, about one-third of new 7th graders moved out of a
school serving grades K-6 and entered a middle school for 7th and 8th
graders, becoming the youngest cohort in the school, while roughly half
of new 7th graders entered a grade 6-8 middle school as part of the
school's middle cohort of students. We find that the effect of
entering a middle school was essentially the same for both of these
groups.
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. We estimate
that an 8th grader who attends school with 200 other 8th-grade students
will score 0.04 standard deviations lower in both math and English than
he would if he attended a school with 75 other 8th graders, the average
cohort size for a K-8 school. This 0.04 standard deviation deficit
represents roughly one-quarter of the largest test-score declines we
attribute to middle-school attendance.
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Given the data we have, we can only speculate about why it is
harder to educate middle school-aged students in large groups.
Developmental psychologists have shown that adolescent children commonly
exhibit traits such as negativity, low self-esteem, and an inability to
judge the risks and consequences of their actions, which may make them
especially difficult to educate in large groups. The combining of
multiple elementary schools and their students also disrupts a
student's immediate peer group. And middle schools often serve a
more diverse student population than many students encountered in
elementary school. Yet while it seems plausible that these changes in
environment would matter, we could not find any evidence in our data
that any one hypothesis can explain the drop in learning among students
moving to middle schools.
Even though a full explanation of the middle-school achievement gap
eludes us, there does seem to be a consensus among New York City
students and their parents that educational quality in the city's
public middle schools is lower than in the boroughs' K-8 schools.
We reached this conclusion after examining responses to a citywide
survey of parents of children in grades K-8 and students in grades 6 and
higher, which was conducted at the end of the 2006-07 and 2007-08 school
years as a part of the city's new school accountability system.
On average, New York City parents of students in middle schools
gave their schools lower marks on measures related to education quality
than parents whose children attend K-8 schools. Figure 4 shows that
parent evaluations of school safety, academic rigor, and overall
educational quality was much lower among those whose children attended
middle schools than among parents with children in K-5, K-6, and K-8
schools. It is important to note that this is not simply a product of
the challenges of educating adolescents. There is little perceptible
decline in satisfaction among parents in K-8 schools as their children
age, a consistency we would not expect if educational quality simply
cannot withstand the onslaught of puberty.
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The students' opinions are consistent with their parents'
assessments, although the lack of data on students below grade 6
prohibits us from more direct measurement of the degradation of
education quality in middle schools. 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.
The Longer View
We don't yet know whether the troubling slide in test scores
for middle-school students persists through the end of high school, a
question that is certainly worth studying. Unfortunately, our data do
not allow us to follow the students in our study further than grade 8.
If the decline does continue, middle schools not only hurt student
achievement in the short term but set students up for unnecessary
longer-term disadvantages.
Of course, it is possible that transitioning to high school could
be more difficult for students who come from K-8 schools than for middle
school students. If K-8 students experience a larger drop in achievement
upon entering high school, that could bring the two groups of
adolescents back into parity. But it is hard to recommend closing the
middle-school achievement gap by bringing everybody down.
The better option is to address the trouble with middle schools--or
do away with them altogether.
Jonah E. Rockoff is associate professor of business at the Columbia
Graduate School of Business. Benjamin B. Lock-wood is research
coordinator at the Paul Milstein Center for Real Estate at the Columbia
Graduate School of Business.