From West Virginia to Arizona, public-school teachers are in revolt. They are demanding better pay, and they deserve it -- so long as their salaries are tied to their performance.
It's not that U.S. teachers are underpaid; the median income for the country's 1 million high-school teachers, for example, is more than 50 percent higher than that of the general population. But relative to peers with similar levels of education, teachers are falling behind. In 1994, public-school teachers madeonly 2 percent less than college graduates in other fields; by 2015, the gap was 17 percent.