America’s expansion to one of the richest nations in the world was partly due to a steady increase in labor productivity, which in turn depends upon the invention and deployment of new technologies and on investments in both human and physical capital. The accumulation of human capital—the...

<DIV>America’s expansion to one of the richest nations in the world was partly due to a steady increase in labor productivity, which in turn depends upon the invention and deployment of new technologies and on investments in both human and physical capital. The accumulation of human capital—the...</div>