Magazine article The Wilson Quarterly
Value-Added Classrooms: Learn More, Earn More
Call it the eight percent solution. According to Eric A. Hanushek, an economist at the Hoover Institution, ousting the worst eight percent of America's public school teachers would produce substantial gains for the nation's economy.
Hanushek has found that a typical student may advance by a year and a half in achievement during a year with a good teacher, but by only half a year with a poor teacher. That can have financial consequences. According to Hanushek's calculations, a teacher in the 60th percentile (based on student scores on achievement tests) raises the average student's lifetime earnings by more than $5,000; a teacher in the 84th percentile raises a student's earnings by $20,000. With classes of 20 to 30 students per year, the increases add up. By the same token, a below-average teacher can diminish a student's earnings.
That's where the eight percent comes in, Hanushek writes in a National Bureau of Economic Research paper published in December. Replacing the bottom eight percent of teachers with merely average teachers would raise American educational attainment to near the top of international comparisons. Based on historical patterns, according to Hanushek, that would raise the U.S. gross domestic product by more than $100 trillion over the next 80 years and increase annual U.S. growth by more than one percent.
But teachers' unions don't think much of the eight percent solution. In a speech in February, Randi Weingarten, president of the American Federation of Teachers, went after Hanushek by name: "We've seen people like Eric Hanushek, who may know a great deal about economics but little about pedagogy, try to reduce teaching to a number--a regression analysis--with the implication being that you can fire your way to good teaching. …