Some recent studies have pointed out something that should seem pretty obvious: teachers continue to improve as they gain experience in the classroom. While it should seem obvious that professional development continues as people become more experienced, the received wisdom as relates to education is that most teachers peak after about three years on the job.

This idea permeates conversations about education, from theory, to policy, to labor discussions, and it is incredibly common among educators and lay people. But researchers at both Brown University and at the National Center for Analysis of Longitudinal Data in Education Research, in two separate studies, have found that this isn’t true.

By using a variety of methods to assess teacher success, they found that teachers continue to improve well after the 3-5 year mark. They also found that teachers were able to boost student test scores by 40 percent between their 10th and 30th year on the job. Test score improvement was more prominent among math teachers than reading teachers, findings based on non-test measurements were better among reading teachers though.

The studies found that more experienced teachers were better at classroom management, and had better student attendance and less student infractions. The National Education Association was quick to embrace this new data, as they have long argued that teaching experience needs to be taken into consideration when dealing with employment and retention of teachers.

Both sets of researchers stressed that the evidence doesn’t point to more experienced teachers being better teachers than their less experiences colleagues. The evidence simply shows that teachers, on average, improve over time. Starting with good teachers and working with them to further improve their skills is essential. These studies coincide with research that points to coaching and professional development helping teachers to improve their performance. Mentor programs, student teaching, and continual education can all help turn a good teacher into a great one, especially if they have the time to develop and put their skills to use.