Room For Growth

A new study finds that high school science and math teachers improve a lot over their first five years on the job, so experience matters.

That’s both good news and bad news. On the plus side, it suggests that novice teachers “have the potential for quickly adjusting their styles to improve students’ test scores,” says Francis Q. Eberle, executive director of the National Science Teachers Association.

But on the negative side, more students today are being taught by novice teachers than by experienced teachers. Thanks to rapid increases in the size of the teaching force and in hiring, the modal value of years of teaching experience—the most frequently occurring value in a data set—dropped from 15 years in 1987–88 to one year in 2007–08, Richard M. Ingersoll and Lisa Merrill of the University of Pennsylvania reported in 2010. Even though novice teachers have the potential for improvement, their current students don’t benefit from that improvement.

Public policy professor Gary T. Henry and graduate student Kevin C. Bastian of the University of North Carolina, Chapel Hill, working with C. Kevin Fortner of Georgia State University, determined teacher effectiveness using North Carolina’s database of scores from the standardized end-of-course tests taken by all students at North Carolina public schools (Science, DOI: 10.1126/science.1215343).

The researchers measured teacher effectiveness in terms of the value added to expected test scores by the teacher. Their model takes into account a number of student characteristics, including previous test scores, to calculate expected scores. If the actual scores were higher than the expected scores, then the teacher was considered to be more effective than if the scores were lower than expected. Ingersoll points out that value-added scores are a controversial measure of teacher effectiveness because of the many factors involved in student performance.

The data suggest that teacher effectiveness continues to increase through about the fourth year of teaching across all math and science subjects. This improvement is particularly pronounced for physics and chemistry. That’s probably because it’s harder for novice teachers to figure out appropriate ways to convey the more challenging material, Henry says.

“The biggest challenge for first-year teachers across the board is learning how to manage their class,” Henry says. “If there was no difference other than that, we would expect all the curves to look the same. It appears that the more challenging the course content, the longer it takes for teachers to fully develop their skills at teaching that content.”

Henry and his colleagues also looked at the impact of attrition on teacher effectiveness. They found that in most subjects, teachers who leave within five years of entering the profession are less effective than those who remain. But for chemistry and physics teachers, exiting teachers are neither more nor less effective than those who remain. There may be a higher bar that ensures that chemistry and physics teachers are more likely to be effective, Henry says. Individuals who leave may do so to pursue other opportunities rather than because they are ineffective teachers, he says.

“If you have a lot of churn in the first few years, you’re losing people before they are able to get better at teaching,” Ingersoll says.

The findings have implications for teacher training, Henry says. “Can we push the preparation earlier and make these teachers more effective from their first day in the classroom?” he asks. “Other work we’re doing now suggests that the more time they spend apprenticing as teachers, the better they are as teachers when they have their own classes.”

Apprentice teachers should spend more time in the classroom developing and implementing lesson plans, he says, so they are better prepared when they have their own classrooms. Also, he believes that better mechanisms are needed for observing, evaluating, and providing feedback to novice teachers.

The extra training is especially important for teachers who must teach a broad range of content. “A lot of principals tell us they don’t want a licensed chemistry teacher,” Henry says. “They want a licensed high school science teacher. Especially in rural high schools, they don’t have enough classes of any subject to hire subject-specific teachers.”

Eberle points out that the study focused on only one measure of teacher effectiveness. He would have liked to see others included. For example, he would like to know whether teachers motivate students to study higher level science. Also, he says, he’d like to see a study that follows teachers into later stages to see whether professional development affects teacher effectiveness and student learning.