Good teachers make a difference.
That hardly qualifies as news. But combined with a serious statistical analysis of how much difference the best teachers can make in the future earnings capacity of their students, that simple declarative sentence gains a certain gravitas.
The New York Times on Friday reported on such a study, conducted by Harvard economics professors Raj Chetty and John N. Friedman and Columbia University's Jonah E. Rockoff. The scientists tracked 2.5 million elementary and middle-school students over 20 years and found convincing statistical evidence that replacing just one poor teacher with an average one could raise an entire classroom's earnings capacity by $266,000 over their lifetimes.
The study went so far as to suggest that other risk factors facing teenagers, such as pregnancy, also were reduced by the presence of good teachers.
The report reinforces the incredibly important role teachers play in our children's future.
It simultaneously boosts the public school reform movement, which seeks to tie teacher performance to student test scores. The researchers tracked the effectiveness of teachers based on test scores, and, significantly, controlled for such variables as poverty, student motivation and other outside factors.
They found that the higher test scores made a difference and, over time, were a strong predictor of the quality of teaching.
The study probably will put wind behind the sails of a reform movement that places increased emphasis on rating teachers based on the test scores of their students.
Such ratings should not be the only way to measure teacher quality, but data clearly indicate that test scores do matter.
Legislators all over the county, including in Missouri and Illinois, have grappled with this dilemma for years. How do you value the complex job of raising test scores of children often unprepared to learn? How do you pay for more comprehensive assessments of teachers when school funding is facing a sharp budget ax?
Existing teacher assessment programs too often consist primarily of a peer teacher or principal making observations in a classroom once a year. A 2009 report from an advocacy group called The New Teacher Project found that in 14 large American school districts traditional assessments had found about 98 percent of the teachers to be satisfactory.
To say the least, that's not likely.
If public schools are going to get more highly qualified teachers in front of students, more rigorous assessments are essential. There is room in this debate to value the job teachers do while recognizing that helping them to improve has a real, tangible effect on the quality of life their students will have after their formal education ends.
Richard Barth, the CEO of the nationally acclaimed nonprofit KIPP charter schools, says that the key to turning around underperforming urban school districts is to "flood them with human capital."
That means finding good principals and teachers and putting them in an environment in which they can succeed.
Having one top teacher for one year can raise a student's lifetime earnings by $9,000, the Harvard study concluded. Do the math and think what top teachers every year could mean.
As our city, state and nation continue to discuss ways to improve our public schools, let's put the numbers to work. Hire good teachers. Value them, and work to make them better.
It's a formula for success.
Copyright St. Louis Post-Dispatch. Reprinted with permission.