Students of teachers who hold certification from the National Board for Professional Teaching Standards achieve, on average, no greater academic progress than students of teachers without the special status, a long-awaited study using North Carolina data concludes.
The study—conducted by William L. Sanders, the statistician who pioneered the concept of “value-added” analysis of teaching effectiveness—found that there was basically no difference in the achievement levels of students whose teachers earned the prestigious NBPTS credential, those who tried but failed to earn it, those who never tried to get the certification, or those who earned it after the student test-score data was collected.
“The amount of variability among teachers with the same NBPTS certification status is considerably greater than the differences between teachers of different status,” says the report. The study examined more than 35,000 student records and more than 800 teachers in the Charlotte-Mecklenburg and Wake County districts in North Carolina.
Mr. Sanders, who manages the value-added assessment and research center at the private SAS Institute in Cary, N.C., said one way to think about the implications of the study would be to envision two teachers with identical experience and education applying for the same job—one holding national board certification and one not. To choose the board-certified teacher over the teacher without the credential would be “only trivially better than a coin flip,” the researcher said.
The Arlington, Va.-based national board offers teachers special certification if they go through a lengthy evaluation process. Many states and districts, in turn, offer financial benefits to teachers who earn the certification.
Sitting on the Results?
The results of the study came to light last week after Andrew Rotherham—co-founder and director of Washington-based Education Sector, a nonprofit think tank—used a posting on his Eduwonk blog to note that the privately organized national board had apparently been “sitting on” the results because they were not favorable.
The board, which has the support of most of the nation’s most powerful education groups, commissioned the research as part of a broad effort, starting in 2002, to examine the worth of its credential. His research findings were completed by late 2004 or early 2005, according to Mr. Sanders.
The board, which has been granting the advanced teaching credential for more than 10 years, posted an “overview” of the research on its Web site last week, though officials there denied the posting was prompted by Mr. Rotherham’s blog entry. They said they did not intend to provide a link to the full study.
The overview is largely critical of the study, citing methodological problems. For instance, the overview said the study lacked a sufficient number of teachers.
“I wouldn’t look at the results as damaging in any way,” said Mary E. Dillworth, the vice president for higher education initiatives and research at NBPTS. “We hope to use this report as well as others for a better certification system.”
Mr. Sanders refuted the NBPTS criticisms in an interview this week.
Despite the findings of his study, he said he believed in the concept of the national board and had been urging officials there to modify the certification process so that it would better reflect the research findings on student test-score gains.
But Mr. Rotherham said in an interview that the board’s failure to be more open about this research was likely to hurt it in the long run. “They have needlessly aroused suspicion about what they’ve done and needlessly handed their critics ammunition,” he charged. “It’s all so … political.”