In a high-profile presser on the economy last Friday, President Obama’s central proposal was to hire more public employees. Then, in his weekly address, he argued that hiring more public school teachers would allow the U.S. to educate its way to prosperity. His Republican presidential rival, Governor Romney, has recommended precisely the opposite: reducing the size of government to boost private sector job growth–and he, too, mentions public school teachers. So… who’s right?

First, let’s look at public school employment and student enrollment over time.

As the chart makes clear, enrollment is only up 8.5% since 1970, whereas employment is up 96.2%. In other words, the public school workforce has grown 11 times faster than enrollment over the past 40 years. What difference does that make in economic terms? If we went back to the staff-to-student ratio we had in 1970, we’d be saving… $210 billion… annually.

Wait a minute, though! Research by economist Rick Hanushek and others has found that improved student achievement boosts economic growth. So if the 2.9 million extra public school employees we’ve hired since 1970 have improved achievement substantially, we might well be coming out ahead economically. So let’s look at those numbers…

Uh oh. Despite hiring nearly 3 million more people and spending a resulting $210 billion more every year, achievement near the end of high school has stagnated in math and reading and actually declined slightly in science since 1970. This chart also shows the cost of sending a student all the way through the K‑12 system–the total cost per pupil of each graduating class from 1970 to the present. As you can see, on a per pupil basis, a K‑12 education has gone from about $55,000 to about $150,000 in real, inflation-adjusted terms.

The implications of these charts are tragic: the public school monopoly is warehousing 3 million people in jobs that appear to have done nothing to improve student learning. Our K‑12 government school system simply does not know how to harness the skills of our education workforce, and so is preventing these people from contributing to our economy while consuming massive quantities of tax dollars. So what would hiring even more people into that system do for our economy…