A second independent study commissioned by the board that offers national certification for teachers concludes that the credential has a positive effect on student achievement.
The report, published last week in the online journal Education Policy Analysis Archives, found that the students of teachers certified by the National Board for Professional Teaching Standards saw greater test-score gains, on average, than did those of teachers without the certification.
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Conducted by Arizona State University researchers Leslie G. Vandevoort, Audrey Amrein-Beardsley, and David C. Berliner, the study is one of some 20 commissioned by the Arlington, Va.-based board in the past two years to examine the impact its teachers are having. The first report found that North Carolina students whose teachers were board-certified fared better on tests on average than their peers in other classrooms. (鈥淔irst Major Study Suggests Worth of National 鈥楽eal鈥�,鈥� March 17, 2004.)
In the new study, which looked at the results of three different standardized tests given to 3rd through 6th graders in 14 Arizona districts, nationally certified teachers were linked to an overall average one-month gain in their students鈥� performance in contrast to others in the same districts.
鈥淚t is like moving the school year from 180 days to 200 days,鈥� Mr. Berliner said. 鈥淭he preponderance of evidence is that most of the time in most subject areas, and in most grades, board-certified teachers are doing a better job of raising student achievement.鈥�
Teachers seeking the voluntary certification from the privately organized board must complete portfolios of their work over a full school year, submit videotapes of their instruction, and take a one-day exam covering subject-matter knowledge and teaching methods.
Board officials hailed the findings as more evidence that the 17-year-old program, which many states encourage their teachers to undergo, is making a difference.
鈥淭his study is providing further evidence that national-board certification is an investment in what works,鈥� said David F. Lussier, the board鈥檚 research director.
A Gold Star?
But some experts say that while the previous report provided solid proof of the effectiveness of board-certified teachers, the Arizona study is not as convincing.
鈥淭his study adds little to our knowledge base,鈥� said Kate Walsh, the president of the National Council on Teacher Quality, a prominent supporter of nontraditional ways of entering the teaching profession. 鈥淭hey sent some 80 teachers in Arizona letters asking them to participate, and less than half said yes,鈥� she said. 鈥淭hat is a clear self-selection bias.鈥�
The study of 35 nationally certified teachers pales, she said, against the North Carolina data. That analysis included more than 600,000 state test scores over three years. Although groups aligned with the council on teacher quality are critical of the certification, Ms. Walsh said, she believes the program provides some necessary recognition and rewards for good teachers.
Others say the test data so far do not prove that the certification process makes teachers better.
鈥淵ou鈥檇 hope the board鈥檚 process would identify better teachers,鈥� said Dale Ballou, an associate professor of public policy and education at Vanderbilt University in Nashville, Tenn. 鈥淏ut are they making anyone better by doing this, or is it simply a gold star given to the best teachers?鈥�
Some 30 states have financial incentives to encourage teachers to participate. North Carolina, which holds the record for the number of board-certified teachers, helps pay the $2,300 certification fee and provides bonuses to those who complete the process.
Whether those states are getting enough of a return on their money, Mr. Ballou said, is up for debate. 鈥淚s it worth the money?鈥� he said. 鈥淭o answer that, there are a whole lot of other questions that need to be addressed.鈥�
Mr. Lussier, the board鈥檚 research director, said other studies are looking at a number of areas where the certification might have an effect.
