Like most school systems that serve disadvantaged children, New Haven, an urban district with a high poverty rate, has faced enormous challenges in improving the quality of instruction. But its political leaders and teachers’ union took a bold step last year in agreeing to a new teacher evaluation system that aims to reward excellent teaching and to retrain or remove poor performers. The first year’s promising results show what can be done when the two sides commit to reform.

New Haven’s path demonstrates that it is possible to hold teachers accountable without crushing morale and wrongfully dismissing good teachers.

Traditional teacher evaluations typically involve cursory observations by school administrators who visit the classroom once or twice — without taking student achievement into account. In most schools, even the least competent teachers receive positive evaluations. Struggling teachers never get the help they need to improve and are locked into place when they receive tenure.

The New Haven system rates teachers individually and gives them the specific help they need. To do that, it focuses on three areas. It considers growth in student learning, as measured by progress on state and local tests and attainment of academic goals. It examines the teacher’s instructional abilities, as measured by frequent observations by principals and other instructional managers. It rates teachers on professionalism, collegiality and whether they have high expectations for all students. Perhaps most important, the system gives teachers almost constant feedback, so that they are fully aware of where they stand and what they need to do to improve.

Teachers who receive the highest rating on a 1-to-5 scale are eligible for stipends and promotion to leadership positions, in which they share skills with colleagues. Those rated lowest on the scale are given intensive coaching and, if they fail to improve, can be dismissed as soon as the end of the school year.

Of the 1,846 teachers rated, 75 were notified early in the 2010 school year that they were in danger of being terminated. Of those, 34 resigned or retired without contesting their final evaluations. Fifteen teachers, considered borderline cases, were given more time to improve and allowed to keep their jobs.

The most hopeful sign is that nearly 40 percent of the teachers who got off to a poor start managed to improve, thanks to extra help. Some who started out as poor performers were rated as “strong” or “effective” by year’s end. This shows that good teaching can indeed be taught, and that with genuine effort school systems can upgrade the teacher corps in a fairly short period of time.