ACCOUNTABILITY may be the hottest word in primary and secondary education nowadays, but it is a recent arrival on the scene. As long as we trusted the existing public school system to do a satisfactory job of educating children, accountability was not an issue.  One was more likely to speak of the system’s “governance,” assuming that conventional public-sector mechanisms—a bureaucracy answerable to elected officials, thence to voters and taxpayers—would furnish whatever oversight and quality-control were needed. One seldom hears talk of accountability in the highway department or the water and sewer agency. The demand for accountability arises when something goes wrong, when people are discontented with an enterprise’s operations or a system’s results—and when they believe that it could work notably better.