The National Education Writers Association (EWA) has released a research brief on teacher effectiveness. Organized around several prevailing questions about teacher effectiveness, the brief seeks to synthesize the available research to help leaders make informed decisions as they develop teacher evaluation systems. The brief reviews over 40 specific research studies or syntheses and interviews with educational scholars. One thing to keep in mind when reading the brief is that nearly all of the studies cited use student test scores as a proxy for student learning, a method still under debate.
1. Are teachers the most important factor affecting student achievement?
Research indicates that teachers are the most important school-based factor; however, out of school factors such as race, socioeconomic status, parent education levels, etc. “swamped most other factors studies as determinants of student test scores.” Decades of research support this claim, with some research indicating as much as 60% of variation in student scores is due to these factors.
In sum, “research has shown that the variation in student achievement is predominantly a product of individual and family background characteristics. Of the school factors that have been isolated for study, teachers are probably the most important determinants of how students will perform on standardized tests.”
2. Are value-added estimations reliable or stable?
Overall, value-added measures do seem to detect some differences in teacher effectiveness, but their estimates can vary widely depending on the controls (e.g., to reduce the effects on the data of factors like race, peer pressure, family income, etc.) selected. Also, the “impact of unmeasured factors in schools, such as principals and choice of curriculum, is less clear.”
3. What are the differences in achievement between students who have effective or ineffective teachers for several years in a row?
The body of research seems to indicate that some teachers do produce stronger gains in student achievement than other teachers. However, estimates of these gains for individual teachers varies year by year, and the impacts of an effective teacher diminish over time. Therefore, the overall effect on students’ learning from having a series of strong teachers is unclear.
4. Do teacher characteristics such as academic achievement, years of experience, and certification affect student test scores?
Teachers improve in effectiveness over their first few years on the job; their effectiveness is sometimes linked with other characteristics such as board certification, content knowledge, etc. “Still, these factors don’t explain much of the differences in teacher effectiveness overall.”
5. Does merit pay for teachers produce better student achievement or retain more-effective teachers?
Merit pay exclusively linked to gains in student learning has not been shown to improve student achievement over time. With regard to comprehensive pay models that incorporate other elements, such as professional development, the research results are mixed; additionally, the jury is still out on the question of whether comprehensive pay models will attract more effective teachers over time.
6. Do students in unionized states do better than students in states without unions?
The body of research on this question does indicate that students in some heavily unionized states tend to perform better than others. However, most studies conclude that it is not possible to determine whether the presence of absence of unions has anything to do with student achievement in these states.
To read the full brief, please visit http://www.ewa.org/site/DocServer/TeacherEffectiveness.final.pdf?docID=2001
