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.
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).
Not exact matches
And the
size of the change in test scores across these consecutive
cohorts should correspond to the change in the
average value added across all teachers in the grade.
With perfect compliance, equal -
sized cohorts, and no dropouts or loss to follow - up, the first stage for the middle school lotteries would be two years, since this is the
average time spent in middle school as of MCAS exams in sixth, seventh, and eighth grade.
The most striking difference across school types involves
cohort sizes (the
average number of students in each grade).
Cohorts ranged in
size from 22 to 31, with an
average of 28.
Within the data, a breakdown of school
cohort size revealed that pupils scored nearly the exact same
average scaled score regardless of
cohort size — although there was a slight benefit of smaller
cohorts in reading.
Because of its much larger
size, the West German figures are close to the German
average (24 % childless for the 1965 — 1969
cohort).
Meanwhile,
average home
size has continued to increase, driving new home prices higher, despite the fact that many among the two largest demographic
cohorts, Millennials and Baby Boomers, are seeking smaller and more affordable housing options.