The idea that teachers stop improving after their first years on the job has become widely accepted by both policy makers and the public. Philanthropist and former Microsoft CEO Bill Gates popularized the notion in a 2009 TED Talk when he said “once someone teaches for three years, the quality of their teaching doesn’t change after that. “. He argued that teacher effectiveness should be measured and good teachers rewarded.
That teachers stop improving after three years was perhaps an overly simplistic exaggeration, but it was based on solid research at the time. In a 2004 article, economist Jonah Rockoff, now at Columbia Business School, tracked how teachers improved over the course of their careers and noticed that teachers improved by leaps and bounds at their jobs. at first, measured by their ability to improve student achievement. test results. But then their efficiency or productivity hit a plateau after three to ten years of work. For example, student performance in their classes could increase by the same 50 points each year. The annual jump in their students’ test scores has not increased. Other researchers, including Eric Hanushek of Stanford University, have found the same thing.
But now a new nonprofit that seeks to improve teaching, the Research Partnership for Professional Learning, says the conventional wisdom that veteran teachers stop improving is one of many myths about teaching. education. The organization says that several groups of researchers have since found that teachers continue to improve, albeit at a slower pace, well into the middle of their careers.
“It’s not true that teachers stop improving,” said John Papay, associate professor of education and economics at Brown University. “Science has evolved.”
Papay cited his own 2015 study with Matt Kraft, as well as a 2017 study of middle school teachers in North Carolina and a 2011 study of elementary and middle school teachers. These analyzes all revealed that teachers continue to improve beyond their first five years. Papay and Kraft calculated that teachers increased student performance by half between their 5th and 15th year of work compared to the first five years of their career. Data is unclear after year 15.
Using test scores to measure teacher quality can be controversial. Papay also watched other measures of how well teachers teach, such as assessments of their ability to ask probing questions, generate lively class discussions, and handle student error and confusion. Again, Papay found that more experienced teachers continued to improve in their profession beyond the first five years of their career. Old dogs seem to learn new tricks.
The debate over whether teachers improve with experience has had far-reaching implications. This has prompted the public to question union pay scales. Why pay more teachers who have been in the job longer if they are not better than a third-grade teacher? This encouraged school systems to fire “bad” teachers, as it was believed that ineffective teachers were unlikely to improve. It is also a way of justifying a high turnover in the field. If there’s no added value to seasoned teachers, why bother retaining them or investing more in them? Maybe it doesn’t matter if thousands of teachers leave the profession every year if we can replace them with lots of new ones who learn the job quickly.
So how come reputable quantitative researchers can come to such different conclusions when they add up the numbers?
It turns out that it is really complicated to calculate how much teachers improve each year. It’s pretty simple to check out their students’ test scores and see how much they’ve increased. But it’s unclear how much of the test score gain we can attribute to a teacher. Imagine a teacher who had a class of struggling students one year followed by a class of high achievers the next year. Bright and motivated students could learn more, no matter who their teacher was; it would be misleading to say that this teacher had improved.
Many other things can affect student test scores from year to year, such as unexpected snow days or natural disasters. We wouldn’t say that most American teachers deteriorated in their jobs in 2020 and 2021 because test scores declined during the pandemic. Other changes, such as switching to a new program, can also affect test results. Wider population changes at school also complicate the calculations. If a city is gentrifying, test scores in a teacher’s classroom can rise significantly, as test scores are generally higher in wealthier neighborhoods. Higher test results, in this case, would probably not be a sign that the teacher improves a lot in teaching.
Economists have to make assumptions when trying to disentangle how much of the class score gain should be attributed to the teacher and how much should be attributed to all the other things that are going on. In Rockoff’s influential 2004 paper, he assumed there were diminishing returns to work experience. This is a reasonable assumption, given that we all have a steep learning curve when we first learn something new, and then the yearly improvements are smaller as we refine our practice. In Rockoff’s data, annual improvements were so minimal by a teacher’s 10th grade that he effectively assumed that teachers stopped improving and plateaued. Arguably, Rockoff guessed what he was trying to study.
When Papay and other economists relaxed assumptions about how teachers generally improve each year, they found that teachers tended to improve better and better by mid-career. But they had to make other assumptions. For example, Papay assumed that new teachers start at the same starting line each year. In other words, the cohort of beginning teachers in 2001 was just as effective as the cohort of beginning teachers in 2009. This might not be true if teacher preparation programs have improved.
I emailed Jonah Rockoff to see if he agrees that science has moved on and teachers are improving throughout their careers. He told me that he still stands by his 2004 analysis and that he generally sees consensus among scholars, not debate. According to his reading of the research, everyone finds the same trends: student achievement increases the most early in a teacher’s career and tends to level off after 10 years of experience. Whether teachers plateau or continue to improve at a very slow pace is not a significant difference to him.
Papay agrees the story is “nuanced” and that mid-career teachers are not showing “significant improvement”.
“It’s not like teachers continue to improve at the same rate they started in their careers,” Papay said. “It’s more modest.”
Whether teachers plateau or improve slowly, the most interesting policy question is whether there are better ways to help teachers improve throughout their careers. Papay and other researchers are trying to determine the kinds of working conditions and in-service training that help teachers thrive. For example, Papay finds promise in pairing teachers to learn from each other, and Kraft studied whether every teacher should have a coach.
Just because inexperienced teachers improve the fastest doesn’t mean professional development should be targeted at them. Rockoff thinks it may be “too early in their careers” for them to get a lot from certain types of training.
Crucially, late-career teachers could improve student outcomes in ways that test scores — or even classroom observations — can’t capture. They could inspire students to go to college or to become scientists or artists one day. This is an inestimable impact but more difficult to measure.
This teacher improvement story was written by Jill Barshay and produced by The Hechinger Report, an independent, nonprofit news organization focused on inequality and innovation in education. Sign up for the Hechinger Newsletter.
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