Does having a teacher who is nationally certified make a difference when it comes to boosting student test scores?
Yes and no, according to a set of working papers published online by the National Center for Analysis of Longitudinal Data in Education Research, or CALDER, a new federal research center based at the Urban Institute in Washington.
Since last year, center researchers have been mining the mountains of student-achievement statistics piling up in states for answers to questions about teacher quality. Under the federal No Child Left Behind Act, states must submit plans for ensuring schools are staffed by “highly qualified” teachers. Yet studies have turned up no definitive evidence on what determines teaching quality and how public policy can affect the hiring and distribution of effective teachers.
The four reports posted last week draw on statistics from Florida and North Carolina. Both states have long-running data systems in place that use student “identifiers” so that researchers can match students’ test scores to specific teachers and classrooms.
While their methods were similar, the researchers came to slightly different conclusions in several areas, including the degree to which more-experienced teachers, or those with better scholastic aptitude, can produce better-than-average learning gains for students.
The working papers are available from the National Center for Analysis of Longitudinal Data in Education Research.
The sharpest differences came on the question of whether teachers who hold certification from the National Board for Professional Teaching Standards are more effective than teachers without that status. Since 1987, more than 55,000 teachers have earned national-board recognition, which involves a lengthy evaluation process.
In their paper, researchers Helen F. Ladd, Charles Clotfelter, and Jacob L. Vigdor, looking at 10 years of North Carolina data on students in grades 3, 4, and 5, found that students in classes taught by nationally certified teachers learned significantly more over the course of a school year than students of teachers without that distinction.
But Tim R. Sass and Douglas N. Harris, in a separate study of Florida students in grades 3-10, concluded that teachers with the credential seemed to be more effective only in some grades, some subjects, or some tests.
“We’re continuing to do studies to try to sort out the reasons for our different findings, but right now we don’t have a particular explanation,” said Ms. Ladd, a professor of public policy and economics at Duke University in Durham, N.C.
Differences in States
But officials at the private, nonprofit National Board for Professional Teaching Standards, based in Arlington, Va., said the differences were not surprising.
“We’re talking about two different states, two different demographics in types of teachers, two different incentive systems for becoming certified, and two different sets of student standards,” said Mary E. Dilworth, the board’s vice president for higher education and research. She noted that North Carolina, which was among the first states to embrace the program of voluntary national certification, offers significant financial incentives for teachers to undergo the process.
Studies conducted by CALDER researchers in both states turned up no evidence that the evaluation process itself improved teaching quality.
The new studies are among more than a dozen that have tried, with mixed success, to link national certification to improved student learning. A research panel convened by the National Academies, a congressionally created group that advises the federal government on scientific matters, is synthesizing that research and is slated to issue a report in November.
Apart from the national-certification question, center researchers found that:
• Teacher experience mattered in both states. In Florida, the boost in productivity associated with more years on the job diminished after eight years. More-experienced teachers in North Carolina, on the other had, kept their edge over less-experienced teachers until their 25th year of teaching. But most of those positive effects came in the first couple of years in the classroom, the North Carolina study also found.
• Florida teachers who had taken more pedagogical-content courses—lessons, in other words, on how to teach specific subjects to pupils at different grade levels—produced better learning gains than teachers who had taken fewer such courses. That was true, the researchers found, regardless of whether teachers had done their coursework on the job or as part of their preservice training. No such positive effects were found for broader pedagogical training or for pure academic subject-matter courses.
• North Carolina students learned significantly more when their teachers held regular teaching licenses, as opposed to emergency or other kinds of state certification, and from teachers who had scored higher on state licensing exams.
“We argue, based on our work in North Carolina, that these teacher credentials do tell us something,” Ms. Ladd said. “And, by any measure you look at it, teachers with lower qualifications are in schools where they are teaching the poorest children,” she added, referring to another paper in the set that examined teacher-distribution disparities in North Carolina schools.
According to Jane Hannaway, CALDER’s director, the center plans to roll out more working papers as findings become available. She said the reports are being termed working papers because, while they have undergone internal review by other center researchers, they have not been formally vetted by the U.S. Department of Education, which is underwriting the 7-month-old center.
