In 2009, McKinsey released a report finding that if we raised our education performance to the level of Korea, we would improve the US economy by a sixth of GDP, or more than $2 trillion. In other words, if our students could read and multiply as well as South Korea, our GDP would add the economic equivalent of Italy.

Here's a new report from NBER reaching a similar conclusion, that the benefit of a good teacher over an average teacher can add more than $400,000 to a student's future earnings. Multiply that out over an economy, and you would see gains in the hundreds of billions.

A teacher one standard deviation above the mean effectiveness annually generates marginal gains of over $400,000 in present value of student future earnings with a class size of 20 and proportionately higher with larger class sizes. Alternatively, replacing the bottom 5-8 percent of teachers with average teachers could move the U.S. near the top of international math and science rankings with a present value of $100 trillion.

In this stratified, winner-takes-almost-all economy, where the middle class has hollowed out and earnings among the college-educated far outstrip high school graduates, the marginal gains from an above-average education will only increase. Read the full story at NBER.