Good teachers help students. Bad teachers hurt them. Now, what do we do with that information?

by David Safier

The NY Times has an interesting article on a phenomenon that's been studied before, with similar conclusions: Good teachers have lasting positive effects on students; bad teachers have lasting negative effects on students.

This seemingly obvious conclusion actually isn't so obvious, and the details are less obvious still.

It would be easy to say good teachers are important but have little lasting effect. After all, the boost in test scores for their students tends to be temporary, fading away in a few years. And really, how much lifelong influence can a good first grade teacher have on students?

It would be equally easy to contend a bad teacher is little more than a temporary blip in a student's education.

But a new study reinforces what has been indicated by earlier studies. Regardless of changes in their test scores, or even their IQ scores, students who have top flight teachers tend to have higher lifelong incomes, fewer out-of-wedlock births, more stable marriages, lower incarceration rates, and so on, when compared with similar students who were in other classrooms. Those positives may not show up on their academic records, but they indicate good teachers somehow influence students' determination to do better. And determination is a huge factor in what people achieve in their lives.

The other side of the coin is, students who have poor teachers tend to go in the other direction, with higher lifetime negatives than similar students who had even average quality teachers.

(The study uses "Value Added" as the measure of a teacher's quality — in other words, the growth in students' test scores from the beginning of the year to the end. For the measure to be accurate, it has to be tabulated over a number of years, since there is lots of year-to-year variation for each teacher.)

To me, this finding makes sense. People talk about how one teacher turned their lives around, made them feel they were worthwhile, turned them on to math or science or music or literature, made that one comment that made all the difference. If a teacher influences students' attitudes about themselves or about an academic field, that can make a world of difference in multiple aspects of those students' lives. If students have a number of top notch teachers during their K-12 years, they are likely to strive for greater success in every aspect of their lives, with positive results.

So if all this is true, the question is, what do we do with this information?

Ideally, we hire more excellent teachers and fewer bad ones. We retain more of the excellent teachers and weed out more of the bad ones. But how do we do that? Is it by making teachers live and die by their students' test scores, which will encourage more teaching to the test and more blatant and subtle forms of cheating by teachers and administrators? Is it by raising the quality of teacher applicants by making the profession more attractive — that  is, raising wages and improving working conditions?

Ideally, we try to get more top quality teachers in schools with low income, low achieving students to help move them higher on the educational, economic and social ladders. But how do we do that? Do we hound teachers in those schools because their students aren't progressing at the same speed as students at high performing schools? Do we pay teachers more to work in those schools to raise the level of applicants? Do we give them lower class sizes, more preparation time, maybe paid summer work time to reward them for the doubly difficult work of teaching those hard-to-reach students?

The conservative, blame-the-teacher "education reform" crowd think they can improve teacher quality by collecting more test data, removing tenure protections and crippling the unions — all while cutting the amount we spend on education. My feeling is, most of their "solutions" are part of the problem. It would be far more valuable to figure out how we can get more potentially good-to-great teachers to enter and stay in the profession than using punitive measures to weed out the mediocre-to-bad teachers who are in the profession in large part because there are not enough top quality applicants.