What Research Shows about the Effectiveness of National Board Certified Teachers

February 26, 2009

The Georgia General Assembly this year is considering legislation that removes incentive pay for National Board Certified Teachers (NBCT). This begs the question: are National Board Certified Teachers "Master Teachers" by definition? What does the research say about the National Board Professional Teaching Standards (NBPTS) process as a whole?

Cavaluzzo (2004) finds positive, statistically significant differences between NBCT and other teachers, but the effects are tiny. For example, after controlling for school and other teacher effects, students of NBCTs might expect to gain "from 7 to 8 percent of 1 standard deviation more than they would have with otherwise similar non-NBC teachers." 

Cavaluzzo also compares the "effect sizes" of NBCT to other types of teachers, as shown to the right. Effect sizes show not only whether a difference is statistically significant, but how significant that difference is.

For context, effect sizes of 0.1-0.3 are often considered "small," around 0.3-0.5 "moderate," and 0.5 or above are "large." 

In other words, this table shows that students of NBCT perform only slightly better than even the students of new teachers who are teaching out of their subject area and lacking certification.

Another, more recent study (Goldhaber & Anthony, 2007) held up as proof of the strength of NBCT in improving student achievement shows similar results. These authors find that the National Board process may identify teachers who are better on average, but that the process itself does nothing to improve student achievement:

"We find consistent evidence that NBPTS is identifying the more effective teacher applicants and that National Board Certified Teachers are generally more effective than teachers who never applied to the program. We do not find evidence that the NBPTS certification process itself does anything to increase teacher effectiveness."

The magnitude of the differences between NBCT and non-NBCT are, as in the Cavaluzzo study, very small, and the authors state that other factors besides NBCT status probably have major influences on NBCT success. Ultimately, Goldhaber and Anthony write that "while the main conclusion the people may take from this paper might be that National Board successfully identifies effective teachers, policymakers would do well to look more closely."

What data does NBPTS use to promote its work?

Even studies supported by NBPTS itself reach similar conclusions. Harris & Sass (2007) write that "We find evidence that NBPTS certification provides a positive signal of teacher productivity in some cases, though the ability of NBPTS certification to identify high quality teachers varies considerably across subjects and grades. There is little evidence that the process of becoming NBPTS certified increases teacher productivity or that NBPTS-certified teachers in a school enhance the productivity of their colleagues."

No matter the source, the research tends to point in the same direction: the NBCT process may sometimes identify teachers already performing above the average, but the process itself does nothing to increase student achievement.

How have NBCT fared in obtaining Master Teacher certification?

Georgia currently has a program administered by the Professional Standards Commission (PSC), which recognizes teachers based on student achievement. In 2005, Governor Perdue signed legislation authorizing the PSC to establish the Georgia Master Teacher Certification Program. To earn this recognition, teachers must show evidence of effecting their students' academic progress and high achievement, either on standardized tests or on classroom assessments that are reviewed by the state for rigor.

To be recognized as a Master Teacher, a teacher must demonstrate that his or her students are performing above the state, system and school averages, and either show progress over time, or evidence of extremely high overall achievement. Data from the first three years of the program can provide a picture of the types of teachers who have successfully earned the Master Teacher recognition:

• In the fall of 2008, 337 Master Teachers were working in Georgia public schools. They had an average of 17 years of experience.
• Overall, 25.6% of Master Teacher applicants earned the Master Teacher recognition.
• 30.3% of teachers who applied using the CRCT-based requirements earned the designation, while 10.2% of those who used the non-CRCT-based requirements earned it.
• 16.4% of elementary school applicants were successful, compared to 41.8% of middle school applicants and 12.9% of high school applicants.

Using these same data, it is possible to show the success rate of NBCT applicants to the Master Teacher program compared to non-NBCT applicants. 

These results are not based on scientific representative samples, but they do support other research findings: NBCT status may help in identifying successful teachers slightly more often than choosing teachers at random, but of the NBCTs who submitted student achievement data for consideration, only 35.1% of them were performing well enough to be named Master Teachers.

Conclusion

The data do not support the notion that NBCT are "Master Teachers" based on that credential alone. The PSC is continuously working to improve the Master Teacher program to make the process the best possible indicator of successful teaching, and to make it more user-friendly for applicants. Finally, Dianne Dunne Wilcox and Chester Finn concluded in 1999 that "The NBPTS is focused on inputs rather than outputs. It is all about the quality of the teacher and not about the impact the teacher has on students." NBCT may succeed in being named Master Teachers at a higher rate than the overall population of teachers, but certainly anyone named a "Master Teacher" in Georgia should have the student achievement results to back up that title.