Inasmuch as a student’s later fifth grade teacher cannot possibly have influenced that student’s fourth grade performance, this curious result can only mean that VAM results are based on factors other than teachers’ actual effectiveness.VAM’s instability can result from differences in the characteristics of students assigned to particular teachers in a particular year, from small samples of students (made even less representative in schools serving disadvantaged students by high rates of student mobility), from other influences on student learning both inside and outside school, and from tests that are poorly lined up with the curriculum teachers are expected to cover, or that do not measure the full range of achievement of students in the class.
Yet in practice, American public schools generally do a poor job of systematically developing and evaluating teachers.
Shepard Every classroom should have a well-educated, professional teacher, and school systems should recruit, prepare, and retain teachers who are qualified to do the job.
Research shows that summer gains and losses are quite substantial.
A research summary concludes that while students overall lose an average of about one month in reading achievement over the summer, lower-income students lose significantly more, and middle-income students may actually gain in reading proficiency over the summer, creating a widening achievement gap.
Indeed, researchers have found that three-fourths of schools identified as being in the bottom 20% of all schools, based on the scores of students during the school year, would not be so identified if differences in learning outside of school were taken into account.