Teachers who leave the profession after their third or fourth year tend to be less effective in that final year of teaching compared to professionals who stayed on, according to a provocative new study appearing in the August/September issue of Educational Researcher.
Authors Gary T. Henry, Kevin C. Bastian, and C. Kevin Fortner began their study with an interesting question: Analyses of large sets of panel data linking students to teachers have documented fairly extensively that teachers seem to gain in effectiveness over their first few years on the job. But is that phenomenon due to improvements in their skills over this time period, or because the weaker teachers choose to leave, thus making the overall teaching pool look better?
To answer that question, the researchers used a value-added methodology to examine matched student-teacher data from North Carolina from the 2004-05 school year through 2008-09 in grades 3-12. They used statewide standardized tests or end-of-course tests, separated out by the year in which the teachers left the state's public schools.
(Value-added, you'll remember, attempts to examine how a teacher has affected his or her students' test scores, controlling for background characteristics, in comparison with similar students in other schools.)
They found that teachers become significantly more effective in their second year on the job, but for those who stay five years, effectiveness seems to level off after the third year in the classroom. Teachers who left after the first year were also less effective on average than those that stayed. So far, those findings confirm others in the research literature, showing that teachers really do get better with experience, at least early on in their careers, while those who really struggle in the field seem to go elsewhere.
Now here's where it gets interesting. The researchers ran 10 different kinds of analytical comparisons, for teachers at each grade level and for math and reading. In 6 of the 10 comparisons, the authors found that teachers who stayed at least five years were more effective during their third and fourth year than were teachers who left following that year. Moreover, the performance of the departing teachers tended to fall during that final year; in 2 of the 10 comparisons, the teachers actually performed worse on average that year than in a previous year.
The authors posit two explanations for the apparent drop in effectiveness among departing teachers. First, they note, tenure is granted after four years of teaching in North Carolina, so these data may reflect individuals who are being ushered out the door due to poor performance. Or, such teachers may simply have reduced their effort once they knew they were leaving.
The study comes to a conclusion certain to provoke debate in this day and age of school turnarounds and teacher accountability. Because of this final-year drop in teaching ability, firing teachers may be less effective in improving students' test scores than investing in efforts to improve early-career teachers' skills, the authors conclude.
They also seem a bit bewildered by the seeming flattening of teacher effectiveness after the third year of teaching.
"Are teachers' habits of mind and teaching practices so firmly in place by that stage that gains in effectiveness are uncommon?" the authors ask.
It's an important a question to think about. Why does teaching ability seem to flatten out so early, and so consistently, in teachers' careers? And more to the point, what can be done to help teachers get even better each year they teach?
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