New CNA Study Finds National Board Certification is Effective Indicator of Teacher Quality

ALEXANDRIA, VIRGINIA — A new study, conducted by CNA (CNA), a non-profit research and analysis institution, found that National Board Certified Teachers (NBCT's) did a better job than other teachers of raising ninth and 10th graders' year-end math test scores in Miami-Dade County, Florida.

The research, which systematically accounted for other factors that could have led to higher scores, found that all else being equal — student characteristics, school environment and teacher preparation — National Board Certified math teachers in Miami-Dade County Public Schools helped their students achieve larger testing gains than did colleagues who had not earned the certification. The study of more than 100,000 student records found that NBCTs were particularly effective with students who have special needs, and also provides some evidence that underserved minority students may receive extra benefits.

The CNA study distinguishes itself in two ways. First, the data set links students to their subject area teacher, and is unusually rich in detail about teachers and the characteristics of their students, compared to many other studies of student achievement. "This is important because the students who are the best prepared to learn are often assigned to the teachers with the best credentials. If the models don't take this into account it is possible to overstate the contribution to learning that is being made by the teacher with these credentials, " said Linda Cavalluzzo, chief investigator of the study, and a senior research analyst at The CNA Corporation's Education Center, which conducted the research.

Second, very little data has been complied on NBC and its effect on student achievement. This is the first study that looks at high school math and NBC. "One of the reasons this study is important is that it presents a diverse set of teacher quality indicators and then uses them to quantify impact on student achievement, while controlling for student characteristics and behaviors — so we got a sharper, more precise picture of what is driving teacher quality and student achievement," said Cavalluzzo.

The research was unique in several other ways. It focused on high school math teachers in an urban school system serving a diverse student population. Many previous studies on the effect of National Board Certification have looked at elementary school teachers in less diverse suburban and rural districts.

Most important, Cavalluzzo's methodology sought to isolate the effects of National Board Certification from other factors that could influence student learning and testing gains, such as teacher experience and education levels, per-pupil spending, school size, student performance above or below grade level and indicators of student motivation, such as teacher-assigned grades in effort and conduct in math class.

Cavalluzzo found that National Board Certification had a greater effect on student math achievement than did state certification to teach math, relatively more teaching experience, or earning a graduate degree. Only having a teacher specifically assigned to math instruction, rather than a teacher who has another primary job assignment, had a larger effect on student achievement than National Board Certification. The only teacher quality indicator in the study that did not clearly contribute to increased student achievement was the competitiveness of the college the teacher attended.

The National Science Foundation (NSF) funded the study, along with the National Board for Professional Teaching Standards (NBPTS), which administers the National Board Certification process. Because other research funded by NBPTS has been criticized for its possible bias towards the organization, NBPTS has been careful to keep an arms length from the research. The NBPTS grant was funded through a competitive process. Research proposals were evaluated by the RAND Corporation. Cavalluzzo presented her findings Nov. 12, 2004 at the Consortium for Policy Research in Education's National Conference on Teacher Compensation and Evaluation in Chicago. The paper, "Is National Board Certification an Effective Signal of Teacher Quality?" is available online at www.cna.org.

All 50 states and more than 500 school districts provide some sort of incentive for teachers to seek NBC. As a result, it is important to consider ways in which NBC can be used to raise student achievement. That process must begin with evidence that the qualities that are important to NBPTS standards and assessments translate to improvements in student achievement. Cavalluzzo's work makes that connection.